HF2-SU3S3

Title sums it's up, as a lot of folks here seem to have had problems. Product arrived two days after ordered. Install was simple. I don't have an ESATA port so I used USB as planned. I have read the complaints about USB 3.0, and can't speak to that as I only have 2.0 ports on my machine. That said, attaching the device to a USB 2.0 port worked fine and was recognized immediately. I first installed two older drives that I had pulled from a dead machine that was not being used. One of the drives I had used and at one time was holding the OS, so I knew it was good. The second drive I had never used before. I installed the two drives without much issue. The structure of the device is not all that heavy duty, but for the cost I found it more than adequate. Once the face plate and the cover we put back on, I hooked into the USB port, and the drives appeared in disk manager, and then cut out. In, out, in, out every few seconds. Pretty frustrating and I began to think that I had a bad controller on the box. I then removed one of the drives leaving the one that I knew was good and the device worked fine. Adding the second drive caused the same problem. I then tried the second drive on it's own and also had the same issues. At that point, I figured it was the Mediasonic, but needed another drive to test and make sure. I do not have a spare controller port to test the drive that I was not sure of. The next day I bought a small used drive a local place to test with. I added it as the second drive in the box and it went in, and then worked perfectly. The second drive was now recognized by drive manager and everything working fine. I guess the the second drive I had has something wrong with it. At some point I'll find a way to test it, but for now I am convinced that the Mediasonic works, and does what is promised. Thoughts: Works fine with USB 2.0 - I know everyone wants faster drive access, but I am using it to stream from that drive, over the USB 2.0 cable, to a Win 7 box, over my network to a WD Live HUB to my TV. Works fine, and is fast enough to watch movies across my network. I don't have a 3.0 port or ESATA so cannot comment on those issues This is not RAID - I assume anyone reading or buying this device knows that already but it is an important aspect. This is exactly what I was looking for, four independent drives. I am using a software product to merge drives and it accesses the Mediasonic device without any problems. For me this is basically a USB HUB with a container for the drives. You want RAID, look elsewhere. A bad drive will make the device act screwy - Based on the issues I had, if you buy this and it keeps connecting and then disconnecting, it may be worth trying each drive individually. I found the one that was causing the problems and removing it solved everything So Far So Good - Just the like the title says. We all know that until you really put some stress on drives and controllers, they may appear to work fine, but really be on the verge of dying. Since I have only had this running for three days, it's hard to say if it is really as good as it has been working so far. Conclusion: At this point I would definintley recomend purchasing one of these. I intend to buy another at this price. I like external drives, and the ability to buy the internal of my choosing, and then be able to stack four in pretty small space is very appealing to me. If your goal is to get some additional storage and have the ability to upgrade the size as you go along, this is a good way to go. Alternately, if you have a bunch of older SATA drives that are not being used, here is a decent way to get them into use on your newer computer. All in all, a good purchase for the price. -P

This is a fantastic hard drive enclosure that has all the essential features I was looking for. After trying several other models, this is the only one that met all my needs. 1. RAID Support: While I don't personally use a RAID setup, it's a great feature to have included, adding to its versatility for future use. 2. S.M.A.R.T. Status: It supports S.M.A.R.T. monitoring, which is crucial for checking the health of your drives. This is an absolute must-have if you're storing important data. 3. Performance: The read and write speeds are excellent and meet my expectations. I was able to get the maximum performance that my hard drives are capable of. 4. Auto-Sleep & Low Power Consumption: The sleep function works perfectly. The enclosure goes to sleep when my computer does. The power consumption is very impressive. I measured it with a smart plug, and with two drives running, it consumed just over 15W. I estimate it would only be around 25W with four drives installed. While my smart plug might not be perfectly accurate or able to measure peak wattage, the overall power draw is ideally low. This is a significant advantage that will save a lot on the electricity bill, especially if you live somewhere with high energy costs like California. 5. Smart Fan & Noise: The intelligent fan is great. It's whisper-quiet when the drives are idle. I use drives that are inherently noisy, so during heavy read/write operations, I can still hear them spinning. However, it's important to note that this noise comes from the drives themselves, not from the enclosure's fan, which remains quiet. Long-term durability remains to be seen, but so far, everything has been working perfectly. Considering its features, performance, and low power usage, I think it offers excellent value for the price. Highly recommended!

( Note: this review is for the ProBox HF2-SU3S2 4-bay JBOD USB3/eSATA Mediasonic model // Non-RAID ) --I purchased this 4-bay enclosure to test Linux + ZFS drive hotswap and see if it would make a decent DAS (direct attached storage) for an old PC. In conjunction with the "StarTech.com 2 Port PCI Express SuperSpeed USB 3.0 Card Adapter with UASP - SATA PEXUSB3S24" (also available here on Amazon) this enclosure has some limitations for ZFS. Environment: Ubuntu 14.04-64-LTS on an underclocked Dual-core (2.1GHz) PC with 4GB of RAM; CPU is not capable of hardware virtualization, but makes a decent ZFS+Samba fileserver/testbox. Enclosure: starting with 1 drive, adding 2 more on the fly, attached with USB3 cable to USB3 PCIe card o 1st try, 1 WD500 Blue drive, not all the way in - ' fdisk -l ' Kernel panic (drive will not slot) Reboot o 2nd try, tried a different drive of the same model and it slotted OK into the enclosure. Drive was detected in both cases when the USB3 cable was hot-inserted into the USB3 PCIe card (enclosure on), AND when the USB3 cable was already in and the enclosure was powered up separately. *NOTE* - there are a couple drives that I have that would not slot into the SATA backplane of this enclosure. YMMV. I was unable to determine why. --The good news is, you CAN insert multiple drives one at a time and they will be detected as separate drives by Linux. --The bad news is, the enclosure DETACHES from the USB bus when you do this, so if you have any Probox-mounted drives you may be risking file/system corruption. (CAVEAT) Test hotswap: semi-FAIL - added 3rd drive, Green, enclosure disconnected existing drives and re-added: Jun 30 06:24:01 p2700dual1404 kernel: [ 636.100286] usb 2-1: USB disconnect, device number 2 Jun 30 06:24:20 p2700dual1404 kernel: [ 654.344522] usb 2-1: new SuperSpeed USB device number 3 using xhci_hcd Jun 30 06:24:20 p2700dual1404 kernel: [ 654.363691] usb 2-1: New USB device found, idVendor=152d, idProduct=0567 Jun 30 06:24:20 p2700dual1404 kernel: [ 654.363697] usb 2-1: New USB device strings: Mfr=10, Product=11, SerialNumber=5 Jun 30 06:24:20 p2700dual1404 kernel: [ 654.363702] usb 2-1: Product: USB to ATA/ATAPI Bridge Jun 30 06:24:20 p2700dual1404 kernel: [ 654.363706] usb 2-1: Manufacturer: JMicron Jun 30 06:24:20 p2700dual1404 kernel: [ 654.363710] usb 2-1: SerialNumber: 152D00539000 Jun 30 06:24:20 p2700dual1404 kernel: [ 654.365802] usb-storage 2-1:1.0: USB Mass Storage device detected Jun 30 06:24:20 p2700dual1404 kernel: [ 654.366189] usb-storage 2-1:1.0: Quirks match for vid 152d pid 0567: 5000000 Jun 30 06:24:20 p2700dual1404 kernel: [ 654.366227] scsi host12: usb-storage 2-1:1.0 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.364678] scsi 12:0:0:0: Direct-Access WDC WD50 00AAKX-221CA1 0125 PQ: 0 ANSI: 6 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.364907] scsi 12:0:0:1: Direct-Access WDC WD50 01AALS-00E3A0 0125 PQ: 0 ANSI: 6 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.365122] scsi 12:0:0:2: Direct-Access WDC WD50 00AADS-00L4B1 0125 PQ: 0 ANSI: 6 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.365614] sd 12:0:0:0: Attached scsi generic sg4 type 0 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.365961] sd 12:0:0:1: Attached scsi generic sg5 type 0 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.366296] sd 12:0:0:2: Attached scsi generic sg6 type 0 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.369464] sd 12:0:0:0: [sdd] 976773168 512-byte logical blocks: (500 GB/465 GiB) Jun 30 06:24:21 p2700dual1404 kernel: [ 655.369559] sd 12:0:0:1: [sde] 976773168 512-byte logical blocks: (500 GB/465 GiB) Jun 30 06:24:21 p2700dual1404 kernel: [ 655.369687] sd 12:0:0:2: [sdf] 976773168 512-byte logical blocks: (500 GB/465 GiB) Jun 30 06:24:21 p2700dual1404 kernel: [ 655.369857] sd 12:0:0:0: [sdd] Write Protect is off Jun 30 06:24:21 p2700dual1404 kernel: [ 655.369865] sd 12:0:0:0: [sdd] Mode Sense: 67 00 10 08 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.370006] sd 12:0:0:1: [sde] Write Protect is off Jun 30 06:24:21 p2700dual1404 kernel: [ 655.370012] sd 12:0:0:1: [sde] Mode Sense: 67 00 10 08 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.370155] sd 12:0:0:2: [sdf] Write Protect is off Jun 30 06:24:21 p2700dual1404 kernel: [ 655.370162] sd 12:0:0:2: [sdf] Mode Sense: 67 00 10 08 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.370330] sd 12:0:0:0: [sdd] No Caching mode page found Jun 30 06:24:21 p2700dual1404 kernel: [ 655.370338] sd 12:0:0:0: [sdd] Assuming drive cache: write through Jun 30 06:24:21 p2700dual1404 kernel: [ 655.370603] sd 12:0:0:1: [sde] No Caching mode page found Jun 30 06:24:21 p2700dual1404 kernel: [ 655.370608] sd 12:0:0:1: [sde] Assuming drive cache: write through Jun 30 06:24:21 p2700dual1404 kernel: [ 655.370624] sd 12:0:0:2: [sdf] No Caching mode page found Jun 30 06:24:21 p2700dual1404 kernel: [ 655.370630] sd 12:0:0:2: [sdf] Assuming drive cache: write through Jun 30 06:24:21 p2700dual1404 kernel: [ 655.469253] sdf: sdf1 sdf2 sdf3 sdf4 < sdf5 sdf6 sdf7 > Jun 30 06:24:21 p2700dual1404 kernel: [ 655.487575] sde: sde1 sde2 sde3 sde4 < sde5 sde6 sde7 sde8 > Jun 30 06:24:21 p2700dual1404 kernel: [ 655.520648] sd 12:0:0:2: [sdf] Attached SCSI disk Jun 30 06:24:21 p2700dual1404 kernel: [ 655.541244] sd 12:0:0:1: [sde] Attached SCSI disk Jun 30 06:24:21 p2700dual1404 kernel: [ 655.562694] sdd: sdd1 sdd9 Jun 30 06:24:21 p2700dual1404 kernel: [ 655.580201] sd 12:0:0:0: [sdd] Attached SCSI disk # fdisk -l /dev/sdd;fdisk -l /dev/sde;fdisk -l /dev/sdf Disk /dev/sdd: 500.1 GB, 500107862016 bytes 256 heads, 63 sectors/track, 60563 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdd1 1 976773167 488386583+ ee GPT Disk /dev/sde: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000afbb5 Device Boot Start End Blocks Id System /dev/sde1 2048 41945087 20971520 83 Linux /dev/sde2 41945088 83888127 20971520 83 Linux /dev/sde3 83888128 125831167 20971520 83 Linux /dev/sde4 125831168 976773119 425470976 5 Extended /dev/sde5 125833216 130027519 2097152 82 Linux swap / Solaris /dev/sde6 130029568 197138431 33554432 83 Linux /dev/sde7 197140480 406855679 104857600 7 HPFS/NTFS/exFAT /dev/sde8 406857728 976773119 284957696 83 Linux Disk /dev/sdf: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0005094a Device Boot Start End Blocks Id System /dev/sdf1 * 2048 52430847 26214400 83 Linux /dev/sdf2 52430848 104859647 26214400 83 Linux /dev/sdf3 104859648 157288447 26214400 83 Linux /dev/sdf4 157288448 976773119 409742336 5 Extended /dev/sdf5 157290496 161484799 2097152 82 Linux swap / Solaris /dev/sdf6 161486848 228595711 33554432 83 Linux /dev/sdf7 228597760 976773119 374087680 83 Linux # ls -al /dev/disk/by-id |grep -v part lrwxrwxrwx 1 root root 9 Jun 30 06:14 ata-SAMSUNG_HD322HJ_S17AJB0SA23730 -> ../../sda lrwxrwxrwx 1 root root 9 Jun 30 06:14 ata-ST3320620AS_9QF4BMH8 -> ../../sdc lrwxrwxrwx 1 root root 9 Jun 30 06:14 ata-TSSTcorp_CDDVDW_SH-S222A -> ../../sr0 lrwxrwxrwx 1 root root 9 Jun 30 06:54 ata-WDC_WD5000AAKX-221CA1_WD-WMAYUL461873 -> ../../sdg lrwxrwxrwx 1 root root 9 Jun 30 06:14 usb-Samsung_Flash_Drive_FIT_0355715090021777-0:0 -> ../../sdb (The following sde,sdd,sdf are the enclosure drives): lrwxrwxrwx 1 root root 9 Jun 30 06:42 usb-WDC_WD50_00AADS-00L4B1_152D00539000-0:1 -> ../../sde lrwxrwxrwx 1 root root 9 Jun 30 06:42 usb-WDC_WD50_00AAKX-221CA1_152D00539000-0:0 -> ../../sdd lrwxrwxrwx 1 root root 9 Jun 30 06:42 usb-WDC_WD50_01AALS-00E3A0_152D00539000-0:2 -> ../../sdf lrwxrwxrwx 1 root root 9 Jun 30 06:54 wwn-0x50014ee6acf2d9c8 -> ../../sdg lrwxrwxrwx 1 root root 9 Jun 30 06:14 wwn-0x50024e920140f1b7 -> ../../sda --Drive read speed on the WD500 Black in the enclosure is VERY good (copying to a motherboard-attached SATA drive): # blockdev --setra 16384 /dev/sdf # read more sectors at once / I/O optimization # time (dd if=/dev/sdf1 of=/dev/sdg1 bs=1M;sync) 20480+0 records in 20480+0 records out 21474836480 bytes (21 GB) copied, 187.885 s, 114 MB/s real 3m12.755s --With straight read speed, I/O is still really good; on average (monitored with iostat) I was getting ~110MB+/sec sustained from partition 1 on the WD 500 Black drive: # time dd if=/dev/sdf1 of=/dev/null bs=1M 20480+0 records in 20480+0 records out 21474836480 bytes (21 GB) copied, 186.264 s, 115 MB/s real 3m6.268s --Good news: The enclosure drives also respond to " hdparm -y /dev/sdX " (instant spindown) and should also respond to " hdparm -S (sleep time) " --The other bad news is that you will not be able to see or do SMART testing on the enclosure drives (from Linux, anyhow): # smartctl -a /dev/sdf smartctl 6.2 2013-07-26 r3841 [x86_64-linux-4.2.0-36-generic] (local build) Copyright (C) 2002-13, Bruce Allen, Christian Franke, [...] /dev/sdf: Unknown USB bridge [0x152d:0x0567 (0x205)] Please specify device type with the -d option. --I need to do some further testing (zfs RAID10 with some disposable 500GB drives) and will update this review as necessary, but so far pretty impressed with this device. It's working with a mix of WD Blue, Green and Black 500GB drives. UPDATE: Further testing with ZFS on USB3 --OK, so I created a ZFS RAIDZ1 pool out of the mixed (3)xWD500 drives: # zpool create -f -o ashift=12 -o autoexpand=on -O atime=off -O compression=lz4 zproboxRZCOMPR raidz \ usb-WDC_WD50_00AAKX-221CA1_152D00539000-0:0 usb-WDC_WD50_00AADS-00L4B1_152D00539000-0:1 usb-WDC_WD50_01AALS-00E3A0_152D00539000-0:2 # zpool status pool: zproboxRZCOMPR state: ONLINE scan: none requested config: NAME STATE READ WRITE CKSUM zproboxRZCOMPR ONLINE 0 0 0 raidz1-0 ONLINE 0 0 0 usb-WDC_WD50_00AAKX-221CA1_152D00539000-0:0 ONLINE 0 0 0 usb-WDC_WD50_00AADS-00L4B1_152D00539000-0:1 ONLINE 0 0 0 usb-WDC_WD50_01AALS-00E3A0_152D00539000-0:2 ONLINE 0 0 0 errors: No known data errors --I then copied ~16GB of data to the pool and ran a test scrub to verify no data issues; I/O was really pretty good, getting ~33MB/sec sustained from each drive and the scrub finished quickly: scrub: Pool: zproboxRZCOMPR - scrub started: Thu Jun 30 09:36:54 CDT 2016 scan: scrub in progress since Thu Jun 30 09:36:55 2016 11.9G scanned out of 23.5G at 102M/s, 0h1m to go 0 repaired, 50.51% done Thu Jun 30 09:38:54 CDT 2016 scan: scrub repaired 0 in 0h3m with 0 errors on Thu Jun 30 09:40:48 2016 o Scrub zproboxRZCOMPR start: Thu Jun 30 09:36:54 CDT 2016 // Completed: Thu Jun 30 09:40:51 CDT 2016 --With everything still powered on, I then removed the middle Green drive(!) --This Failed the whole pool - after the enclosure "bounced", drives were re-added to the system as sdg,sdh: # la /dev/disk/by-id |grep -v part lrwxrwxrwx 1 root root 9 Jun 30 08:45 ata-SAMSUNG_HD322HJ_S17AJB0SA23730 -> ../../sde lrwxrwxrwx 1 root root 9 Jun 30 08:45 ata-ST3320620AS_9QF4BMH8 -> ../../sdf lrwxrwxrwx 1 root root 9 Jun 30 08:45 ata-TSSTcorp_CDDVDW_SH-S222A -> ../../sr0 lrwxrwxrwx 1 root root 9 Jun 30 08:45 usb-Samsung_Flash_Drive_FIT_0355715090021777-0:0 -> ../../sda lrwxrwxrwx 1 root root 9 Jun 30 09:45 usb-WDC_WD50_00AAKX-221CA1_152D00539000-0:0 -> ../../sdg lrwxrwxrwx 1 root root 9 Jun 30 09:45 usb-WDC_WD50_01AALS-00E3A0_152D00539000-0:1 -> ../../sdh lrwxrwxrwx 1 root root 9 Jun 30 08:45 wwn-0x50024e920140f1b7 -> ../../sde --I tried copying more data to the pool and it hung hard: # zpool status pool: zproboxRZCOMPR state: ONLINE status: One or more devices are faulted in response to IO failures. action: Make sure the affected devices are connected, then run 'zpool clear'. see: http://zfsonlinux.org/msg/ZFS-8000-HC scan: scrub repaired 0 in 0h3m with 0 errors on Thu Jun 30 09:40:48 2016 config: NAME STATE READ WRITE CKSUM zproboxRZCOMPR ONLINE 0 439 0 raidz1-0 ONLINE 0 4 0 usb-WDC_WD50_00AAKX-221CA1_152D00539000-0:0 ONLINE 3 4 0 usb-WDC_WD50_00AADS-00L4B1_152D00539000-0:1 ONLINE 3 2 0 usb-WDC_WD50_01AALS-00E3A0_152D00539000-0:2 ONLINE 3 2 0 errors: 439 data errors, use '-v' for a list ( had to reboot here; left the green drive out to simulate failure ) pool: zproboxRZCOMPR state: DEGRADED status: One or more devices could not be used because the label is missing or invalid. Sufficient replicas exist for the pool to continue functioning in a degraded state. action: Replace the device using 'zpool replace'. see: http://zfsonlinux.org/msg/ZFS-8000-4J scan: scrub repaired 0 in 0h3m with 0 errors on Thu Jun 30 09:40:48 2016 config: NAME STATE READ WRITE CKSUM zproboxRZCOMPR DEGRADED 0 0 0 raidz1-0 DEGRADED 0 0 0 usb-WDC_WD50_00AAKX-221CA1_152D00539000-0:0 ONLINE 0 0 0 10918954850413458013 UNAVAIL 0 0 0 was /dev/disk/by-id/usb-WDC_WD50_00AADS-00L4B1_152D00539000-0:1-part1 usb-WDC_WD50_01AALS-00E3A0_152D00539000-0:1 ONLINE 0 0 0 errors: No known data errors ( re-inserted green drive in the enclosure here - Hotswap ) ( tried ZFS scrub -- hung hard ) [ 221.415966] WARNING: Pool 'zproboxRZCOMPR' has encountered an uncorrectable I/O failure and has been suspended. # zpool scrub -s zproboxRZCOMPR cannot cancel scrubbing zproboxRZCOMPR: pool I/O is currently suspended ( reboot again, leaving green drive in ) pool: zproboxRZCOMPR state: ONLINE status: One or more devices has experienced an unrecoverable error. An attempt was made to correct the error. Applications are unaffected. action: Determine if the device needs to be replaced, and clear the errors using 'zpool clear' or replace the device with 'zpool replace'. see: http://zfsonlinux.org/msg/ZFS-8000-9P scan: resilvered 24K in 0h0m with 0 errors on Thu Jun 30 10:02:17 2016 config: NAME STATE READ WRITE CKSUM zproboxRZCOMPR ONLINE 0 0 0 raidz1-0 ONLINE 0 0 0 usb-WDC_WD50_00AAKX-221CA1_152D00539000-0:0 ONLINE 0 0 0 usb-WDC_WD50_00AADS-00L4B1_152D00539000-0:1 ONLINE 0 0 1 usb-WDC_WD50_01AALS-00E3A0_152D00539000-0:2 ONLINE 0 0 0 errors: No known data errors --After rebooting with the missing drive in again, ZFS now sees the whole pool and responds OK to scrub: Pool: zproboxRZCOMPR - scrub started: Thu Jun 30 10:05:40 CDT 2016 pool: zproboxRZCOMPR state: ONLINE status: One or more devices has experienced an unrecoverable error. An attempt was made to correct the error. Applications are unaffected. action: Determine if the device needs to be replaced, and clear the errors using 'zpool clear' or replace the device with 'zpool replace'. see: http://zfsonlinux.org/msg/ZFS-8000-9P scan: scrub repaired 0 in 0h3m with 0 errors on Thu Jun 30 10:09:35 2016 config: NAME STATE READ WRITE CKSUM zproboxRZCOMPR ONLINE 0 0 0 raidz1-0 ONLINE 0 0 0 usb-WDC_WD50_00AAKX-221CA1_152D00539000-0:0 ONLINE 0 0 0 usb-WDC_WD50_00AADS-00L4B1_152D00539000-0:1 ONLINE 0 0 1 usb-WDC_WD50_01AALS-00E3A0_152D00539000-0:2 ONLINE 0 0 0 errors: No known data errors o Scrub zproboxRZCOMPR start: Thu Jun 30 10:05:40 CDT 2016 // Completed: Thu Jun 30 10:09:37 CDT 2016 Conclusion: At least in USB3 mode, I would not recommend this particular enclosure for Linux+ZFS unless you are willing to put up with reboots in case of drive failure. It's probably fine to use with new drives that have been burned-in/tested as long as you have everything backed up; for all I know it may be more reliable with swapping drives under Windows. I wish the manufacturer had some kind of update that would not cause the whole enclosure to essentially "reboot" in case a drive is removed or inserted, the whole point of having a SATA backplane is for hotswap. If you're serious about your data, I would also recommend plugging this into a UPS instead of just a power/surge strip. Just MHO. UPDATE: The enclosure DOES work as you would expect in eSATA mode - hotswap on a 3-drive RAIDZ1 works without unmounting/faulting the whole ZFS pool. AND you can access the SMARTCTL data on individual drives. :-) Might be a slight performance loss, but certainly merits further testing. And of course, you need to attach it to a SATA port that supports port multiplication (which my old Gigabyte motherboard does.) Very happy now. UPDATE 2017.April: I'm very happy with this enclosure - it's still going strong and I've been using it for laptop ZFS demos in eSATA mode :)

Edit - So, after having this enclosure for over a year, I've knocked it down to 1 star. I was very pro Mediasonic when they first showed up with this product (I was one of the early adopters) and have recommended this box to a number of my friends. However, ever since I got it, I had USB 3.0 issues with intermittent disconnects. I tried everything possible and flashed numerous firmwares, tried USB 3.0 PCI cards but to no avail. At the time, the Mediasonic customer service rep kept telling me it was an issue with my hardware and that because USB 3.0 was a nascent technology, it needed more mature drivers from the vendors for my motherboard/PCI USB 3.0 cards. Fast forward to a few weeks back and I just built a new HTPC with the latest and best motherboard that has integrated USB 3.0 ports. Still the same issues though. I even bought a Mediasonic USB 3.0 PCI card on their recommendation but with the same problem. Turns out that there might be a possibility that it is a faulty controller card in the box (another reviewer on Amazon had the same issue as me and it got sorted out when they sent him a new card). So I reached out to Mediasonic to point out that this was a failing on their end and not an issue with my hardware as they had led me to believe. However, they only way they would even try to fix the issue is if I mailed out my controller card on the box to them, have them test it and then send out another card - leaving all my data inaccessible for weeks. I made the seemingly reasonable request that they send me the card first and that after installing it, I'd send them back the faulty card. To that they responded by reminding me about what a big favor they were doing to me by going out of their way to try and fix their defective product. I supported Mediasonic because they seemed to be a small company focused on providing quality products at a reasonable price point with good customer service. It turns out I was clearly mistaken and their customer service is pretty poor and they aren't going to make any extra efforts to make things right with their customers. I guess I learned my lesson for being an early adopter of a product from a young, untested company. My advice to you, stay away from this product because the USB 3.0 is flaky at best and there are tons of people complaining about it here and on their forums. They keep blaming it on drivers and firmwares and will send you on a wild goose chase installing everything under the sun on your computer till they finally blame the issue on your hardware. I was willing to accept that when the product first came out, but now, after having tried 2 different motherboards and 2 different PCI-E cards over the span of 1.5 years, it is clear to me that the issue is with their product and not my hardware. Old review below ---------------- I spent a few days looking for a good enclosure and suddenly I came across this Mediasonic enclosure which I had never heard off. It seemed perfect for what I wanted, a USB 3.0 enclosure that didn't charge you extra just for some cheap hardware RAID implementation. Since I was planning on using a software RAID solution (FlexRAID) for my 4x2TB set up, this was perfect and it saved me some money. Pros: - Looks very nice and has a nice form factor - Fan at the lowest setting (which is all you need for the new hard drives that run a lot cooler) is barely audible. Also, if you really need it, the highest Fan speed will definitely guarantee that your hard drives will stay cool - USB 3.0 and e-SATA work great. Was getting excellent speeds (over 100MB/s, limited by my motherboard) - Outstanding customer service and support on their forums (mediasonic.ca) and via email. Had trouble with a faulty USB 3.0 card and they helped me out quite a bit. Ended up buying the Mediasonic USB 3.0 PCIe card and that plays along very nicely with my PC and this enclosure. Cons: - Really can't think of any. I am definitely going to buy another one once I start running out of space.

ORDERED: March 16, 2012 (a Friday, 3-5 business day shipping) SHIPPED: March 19, 2012 ARRIVED: March 21, 2012 (arrived Wed. morning) *Amazons estimate was the 27th, UPS had a correct estimate of the 21st. SHIPPING: Shipped from Canada in an inside out USPS priority mail box (odd - no idea why). I've never seen a box with so much tape on it. Every corner and crack had a thick strip on it. Inside there was one long sheet of bubble wrap protecting the product box. The box comes with 4 handles on it that require 2 screws to mount the handles on (little screwdriver included - very nice of you). When HDD's are in the bays, pulling the handles down gets past the initial tension of pulling the drives off the sata ports. The drives themselves aren't held tight near the port so you can angle the drives a bit. You have to eyeball it and used "the force" to feel if the angle of the drive is right over the port before pushing down. When the HDD's are pushed down, the handles follow a groove and lock the drives down. So the handles lock the drives in place as well as give the initial pull to remove the drive off the port. The con here is you only get 4 handles so you cannot have extra drives for hot-swaping pre-mounted. The outer door if let drop past 90 degrees will fall off - it's not physically locked to the case. This can be a bit annoying at first but it's nice to have the option for the outer door to be all the way off. The inner door has two pressure tabs at the top and a thin edge at the bottom that goes into a thin slit at the bottom of the case. This as well comes completely out. It can be slightly annoying to get the bottom of this inner door back into the groove. Once locked into place though, it's solid and doesn't move. I guess with this and the locking handles combined, even a good drop should not be enough to cause the HDD's to move. Fan on low or medium is much quieter than my PC (Coolermaster HAF 932). On low it's pretty silent. The included product sheet comes with instructions for adjusting the fan screws to reduce noise. Also a nice plus is that this is an external fan mount (really thoughtful feature - thank you). External fans are rare for devices like this and I appreciate it. The side A/C plug I don't like at all though. USB 3.0: Awesome. I'm getting an average of about 120MB/s. eSATA: The Unit does not see an eSATA connection at all. This is on my rear MOBO eSATA port that I've been using with an external Thermaltake eSATA dock on for a long time. I know the port is good. I think from reading it may be this device needs a powered eSATA multi-port connection. I'm not sure at all though - it seems like it should at least see the port and show drive 1? The annoying part here is that with the USB at 120MB/s average - that's is PLENTY good enough for me. I guess since an eSATA card is only $20 or so I'll go ahead and order one. But, I dislike the idea of throwing a card in just to verify the eSATA port on this device works. Right now as far as I know it's doesn't work and the only way I know to find out for sure is to put in a eSATA card that's known to work with this device (recommendations welcome - thanks). If it's dead I'll send it back or cross-ship for a replacement. Stuff happens. I'd only be upset if there was a problem like a dead port twice in a row. OTHERWISE (with USB 3.0): I turned the unit on and the drivers were ready and available to Windows in just a few seconds. I've always used eSATA and have never used my MOBO's USB 3.0 port - I'm rather pleased with the speed it's getting. My internal eSATA to eSATA average transfer speed is about 83MB's (hopefully I didn't screw up and put a drive on a eSATA 3GB/s connection instead of a 3GB/s connection. Right now the external USB 3.0 connection is almost 40MB/s faster than on of my internal eSATA drives. RATING: I want to take off 1 star for the lack of extra handles and the side mounted power connection. But, otherwise I'm pleased and got what I wanted and what was advertised. Just from looking at the package content I knew ahead of time this had no spare handles and a side mounted power connection. I got what I paid for so I can't really take a star off for it. I've already copied around 2TB of data and watched a movie off it through a media server since I got it earlier today. Everything (except it's eSATA port?) is working great. And, the noise is very low. I also like how it turns off with the system - although there should be a dip switch or something where you can choose for it to auto-power up with the PC as well (maybe there is and I don't know yet). I wish they would have left out the little screwdriver (I have like 50 around the house probably) and used those few cents to instead throw in extra HDD handles. MY HARDWARE: ------------ MOTHERBOARD: Asus Sabertooth P67 rev 1 (released April 2011) EXTERNAL eSATA PORT: jMicron JMB362 3Gb/s external port *Supports Port Multiplier with Command-based Switching on SATA II port *limited support *external eSata is does not support POWERED multiport USB 3.0: NEC USB 3.0 controller - no idea what the model number is for it.

So far this product works OK - with caveats. After receiving my unit I initially installed five 8TB Seagate Exos drives, and now I've added three more to fully load it with 8 drives. While I was successful at getting the drives installed, the mechanical alignment guides are not good. The drives are not installed with a caddy, but a plastic handle is attached to each drive and, when the drive is installed, the inner doors apply pressure to these handles to ensure the drives can't back out of the SATA connectors. It's an OK system, but the drive alignment to the SATA connectors on the backplane can be a problem. Not an impossible problem if you are careful and have patience. For me, the bottom drive was by far the most difficult to get aligned as the bottom of the metal frame for the drive held the bottom drive slightly too high for easy connector insertion. I kept swapping drives around and coming in at different angles until it mated. This mis-alignment will likely put pressure on the SATA connectors that would normally be supported by the mechanical frame. It works and will probably be OK for consumer use. After all, this is an inexpensive enclosure. My second concern is related to the thermal management of the enclosure. I've run a temperature experiment several times with the same outcome. During a multi-day drive burn-in, I monitored each drive's temperature through the SMART data. The fans are configured to pull air through the enclosure, and the only venting through which the fans can pull air is located towards the bottom of the front (beneath the outer plastic door with the key lock). The fans will change speed based on load, but even at the highest fan speed some of the drives will creep into the lower/mid 50degC range. There is a spread of temperatures across the drives. However, if I open the front plastic door then all of the drives are in the mid 40degC range, which is fine. The cooling/airflow is certainly not optimal for the configuration. Based on my simple experiments, I would say that adding vents to the outer door would give a drastic improvement in cooling for some drives. I've not taken the time to add my own thermocouples to the enclosure. In general, this enclosure is a good deal for what it is. There is certainly room for improvement that shouldn't add to the product cost. For me, the electrical performance of the unit has been solid. I've completed one 5-day drive burn-in sequence with no errors on the drives or with the enclosure. I've connected this enclosure to a Protectli mini-PC running ProxMox and am using a Ubuntu Desktop virtual machine with two assigned CPU's to do the drive burn-in. The burn-in process is taking 50-60% of the two CPU cores. .... I'm adding to this review after several weeks of using the product. The bearing on one of the cooling fans is starting to rattle, so the fans will have to be replaced on the unit that I received. This is an incredibly short life cycle for the fan as they are rated for 35,000 hours, which is 4 years. One of mine didn't make it for 4 months without a noisy bearing/pending failure. Luckily, the fans are readily available through multiple sources. As part of my burn-in process, I tested read and write throughput on all combinations of 1,2,3,4,5,6,7, and 8 drives (test script). In general, the enclosure operated up to the speed of the drives themselves (in my case each drive can handle 240-250MB/s) when 4 or fewer drives were tested in parallel (there were some instances where one drive may have been lower throughput, but this could have been the OS causing this and not the hardware). For the 6-drive tests (my standard use case), the R/W throughput was down to around 150-180MB/s for most cases. For the 8-drive case, all drives were around 150-160MB/s or 1.2GB/s combined throughput. This lines up with the 10Gbit/s interface throughput. So, I'm happy with the electrical hardware performance. I've had no interface errors so far under Proxmox using virtual machines as test platforms, but I did have to pass though the whole Thunderbolt device (PCI device) and not just the Thunderbolt port itself on the Protectli mini-PC platform. When I passed through just the Thunderbolt port I had periodic lock-ups (apparently a known issue in Proxmox and not an issue with the drive enclosure). Once I passed the Thunderbolt port to the VM using the preferred method, I've had no problems after weeks (literally) of burn-in and performance testing. So my initial impression is unchanged after several weeks - electrically this product performs as expected, but mechanically/thermally there is room for improvement. However, for the cost, this is a good solution if you are patient and are aware of the mechanical limitations.

I have two of these boxes; both are configured as RAID boxes and have been in continuous use for years -- one of them since 2013. (One is RAID 10, the other RAID 5.) In that time I have had to replace three hard drives in the in-use units. At various times each box have been moved between USB and eSATA connection to the host PC. Both have always been consistent, solid performers. Neither has ever given me any trouble. WHAT IT IS: This is a simple and cost-effective external device. It functions well in either USB or eSATA mode. The box is self-contained and plug-and-play; it requires no drivers and adds little or no extra load to the host PC. I have never had a PC or Mac (with appropriate configuration) fail to recognize the box and "talk" to it as expected. In any RAID configuration, it appears and behaves just like any external hard drive. As JBOD, it shows up as multiple separate external devices. Within the limits of what it is and how it works with the connected computer (discussed more below), it just works and has always been extremely reliable. But you should think through what you are getting at this very economical price point (economical for a RAID box, that is). The device detects the power state of its connection to your computer; it will turn off automatically when you power down your computer and will power back up when you turn the computer back on. This is a FEATURE and is the intended operation. You do NOT have to turn it off and on manually. For many this is a great convenience. It is also a good thing for power and heat saving (as well as hard drive life span and reducing noise when the computer is not on). But it can also be a negative depending on your use case (more on this below). In either SATA or JBOD or using eSATA or USB, I have never had a lick of trouble; the box just works. Lights on the box correctly indicate drive use and will tell you when a drive has failed. Power down and replace the failed drive; when you power back up in RAID mode the box will proceed to rebuild the array with no further action from you. (In JBOD mode, the new drive shows up in your operating system -- though of course you may need to go into disk manager to partition and format it before Windows can use it.) In terms of value for money, the performance is great for this price. WHAT IT IS NOT: You do get what you pay for. This is a very economical / cost-effective unit (for a multi-interface RAID unit). The device talks via eSATA OR USB. Most home-user class computers will not let you use both interfaces at the same time. For example: If you connect both at the same time, a Windows PC will only recognize the device on the eSATA connection (since the SATA bus is usually initialized before USB). Though the device does accept SATA III hard drives and works internally at 6Gb/sec speeds, it can only sustain those speeds to your computer when configured as JBOD. When configured for RAID it can only support 3 Gb/sec speeds (equivalent of SATA II, closer to USB 2 than 3 speed). That makes it great for backup and fine for accessing files one at a time (even playing music), but maybe not really solid for video streaming or disk-intensive gaming applications. The ventilation system is less than spectacular and needs to be kept clean or else lint buildup will make airflow a drive-killing problem over time. When closed up properly, the automatic fan settings on this box will make the drives inside tend to run hot (using HD Sentinel to monitor individual drive SMART temp reporting). That said, I have run these units for years on end without encountering unexpected / premature drive failure. I have also found the manual "high" fan setting works pretty well and is still pretty quiet -- not really noticeable if sitting under the desk. The unit will also run just fine with the front door down (open), which will cool everything down and keep it at more "normal" HD operating temps. The box front can be opened and closed without disturbing the drives inside while the unit is running (just be careful not to jiggle or move the box itself or drives inside while running). All box functions work just fine when the front is not closed, if you want increased cooling. (Just don't forget you left the box open when you are working around it or go to move it!) This box will NOT magically transform all the vagaries of PC external connectivity into the reliability of permanently connected internal drives. It is NOT a high-end NAS or internal RAID system powered by an expensive and high-capacity controller. All bets are off if you move the unit and/or accidentally jar or disconnect the cable when the unit is running -- or if your computer's power saving settings turn off the connection to this unit. I have found the system works consistently as designed as a solid SATA II drive when connected via eSATA or USB (assuming the cable isn't accidentally jolted loose). You can use this box and it will be reliable attached to an always-on computer -- but first you need to expect to spend configuration time and might encounter some frustrations along the way. To get reliable, always-on connectivity with no unexpected disconnects, you are going to need to spend some time checking your computer BIOS and several settings in the operating system. Power saving settings that shut down your hard drives (SATA) or dormant devices (USB) will work just fine with internal and some external devices, but I hope it is obvious that they will cause this box to turn itself off. When the connection gets powered down, the device will see that as your PC turning off and in response it will turn itself off (which is exactly what it is supposed to do, as mentioned above). Since the device is driverless, there is no software to keep it alive or magically reconnect it when/if you return and want to use it. When that happens, the only recourse is to power down your PC, then restart. It took me several tries to find and disable the various PC and operating system power-saving features; once I did that -- ensuring the PC / operating system did not time out / turn off its USB or eSATA connections -- the Mediasonic box became absolutely solid and reliable, working predictably in harmony with the PC to which it is connected. Once everything was configured, it became another always-there drive that just.plain.works. As noted, this device does not come with external monitoring/control software. Out of the box, you need to look at the lights on the front to affirm it is configured and operating properly. There is no software pop-up or alert on your computer desktop if your RAID array is degraded -- you have to actually look at the box. If you forget to look at the box, you might not notice a drive has failed until it's too late to rebuild the RAID array. On the flip side, those lights on the box do correctly indicate hard drive activity inside the box and do indicate if a drive has failed (or, once you replace the failed drive, when a RAID array is rebuilding). The lights are accurate but do not give you much of an indication as to progress of built-in functions; you're not going to get much of a clue as to how much longer that RAID rebuild is going to take. However and FWIW. I have found this device does correctly pass all needed information through for most disk diagnostic applications. HD Sentinel works well and accurately to report the status of every constituent disk drive (even when configured in RAID mode so that Windows thinks its just one big drive). I have also found by trial and error that several software distributions that come with other external RAID systems will also correctly read and report status of these boxes -- thought they still won't let you remotely configure or adjust what the RAID controller is doing. (For example, the software that comes with Sans Digital units will read and report on these Mediasonic boxes when configured as RAID units.) Your mileage may vary. Overall, this box is everything I had hoped and I have found it completely reliable. A bargain at a $150 price tag.

I have a 2012 Mac Mini with USB 3.0 and was looking for an inexpensive way to add some external storage. I already had four WD 1TB hard drives (two Black and two Green), and wanted a solution where I could create a software RAID 10 span/mirror array for 2TB of storage. After reading up on this model it sounded like a good fit, so I ordered one. My primary concern was noise. The 2012 Mac Mini is a VERY quiet computer - Apple has tweaked the fan speeds so that there is hardly a whisper unless the CPU is really cranking heavily (e.g. rendering video). With some trepidation I added my four 1TB hard drives (a very simple process by the way), plugged in the power, and fired it up. I am VERY pleased at the low noise level. I have the ProBox positioned under my desk and it is literally inaudible. Even if it were on top of the desk, the noise level is as quiet or quieter than the Mac Mini itself. Build quality is quite good. Some have noted the unusual power connection on the side; in my installation this didn't affect anything but I suppose it could for some people. The blue LEDs are pretty bright but that doesn't affect things under my desk at all; if it were used in a home theater setting that might be a different story. As far as installation, all that's needed is to fasten a handle to the front of each hard drive (a screwdriver is actually included in the box for this). Then slide each drive into its slot, snap a cover plate over the drives that holds them in place, and press the front panel into place. I ran the included USB 3.0 cable from the ProBox to my Plugable 7-port USB 3.0 hub, powered it up, and all four disks were quickly recognized and mounted to the OS X filesystem. Previously I'd used each of these disks individually in a Plugable USB 3.0 docking cradle, so all four drives were formatted and had data on them - all were recognized instantly and worked just as they had in the dock. For test purposes, I left the drives alone for a day and let Time Machine push some data to them. Only one glitch, at some point overnight the ProBox turned off. My Mac is set to never sleep, but possibly the ProBox thought it saw the Mac (or the hub) power down momentarily, and turned itself off since that's the default setting for its "Synchronization mode". I disable Synchronization with the control panel button and it hasn't hiccuped since. Once I was satisfied that the enclosure worked OK and did some BlackMagic speed tests to verify the speed was comparable to my old USB 3.0 dock, I created a 2TB RAID 10 array using all four 1TB disks. I used Apple's Disk Utility to create two 1TB Mirrored arrays (RAID 1) of two drives each, then joined those two arrays into a single 2GB Span (RAID 0). Then I copied about 860GB of data from my internal 1TB drive over to this new array, freeing up space on my internal Fusion drive. Given the very reasonable cost, the always appreciated Amazon Prime 2-day free shipping, and the very simple setup and configuration, I am giving this product a 5 star review without hesitation. Addendum December 2013: The ProBox is still going strong, not a single hiccup with 24/7 operation. I did change out the config over the summer though - now I have two 3TB disks in a RAID1 mirror as my primary data array, and the two original WD Green disks in a RAID1 array being used as a backup drive for other Macs in the house (via OS X Server). All is working smoothly, still very happy with my purchase. Addendum October 2015: The ProBox has continued to work well, though I've just retired it and replaced it with a Drobo 3rd generation 4-bay RAID system to give me a little more ease of expansion. Certainly this has been a heck of a nice unit for me and you can't beat the $100 or so price.