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[c128]

I'll apologise now for a bit of a cross-post - I also posted this on the plugincomputer.org forums but without reply .

I'm waiting on a Sheevaplug, and my long term aim is to use it to replace my current Intel-based file server.  This file server uses 4x500GB SATA drives, and as I'd really like to re-use these drives with the Sheevaplug, I've been looking at suitable USB SATA enclosures.

General USB SATA drive enclosures seem mostly to be single drive, although I've found a couple of dual drive enclosures and, most interesting for me, this:

http://www.startech.com/item-download/SAT3540U2E-35in-4-Drive-eSATA-USB-Multi-Bay-External-Hard-Drive-Enclosure.aspx

...so that's an enclosure that will take 4 SATA drives and offer them up on a USB interface.

Information seems to be thin on the ground, although there's a manual downloadable from the above - I can find no reviews and (relatively) few distributers, let alone Sheevaplug users.  However, it does look like they're available here in the UK for around £116, which isn't too bad if you tot up the cost of 4 single enclosures or 2 duals, and it would make things quite neat.

However...would I be asking for trouble using something esoteric like the above as my file storage in a Sheevaplug based file-server setup?

[NewIT_Marcus]

This is the closest that we have:

http://www.scan.co.uk/Products/Sharkoon-SATA-QuickPort-Pro-Duo-USB-eSata-Desktop-Docking-station-for-2-SATA-HDDs-%2825-35%29

Logicially it is similar, because the one USB port allows access to multiple drives (ie it is a hub of sorts - and because of that, I don't believe you will be able to boot from one of the drives).

dmesg:

Code: [Select]

usb 1-1: new high speed USB device using orion-ehci and address 3
usb 1-1: configuration #1 chosen from 1 choice
hub 1-1:1.0: USB hub found
hub 1-1:1.0: 4 ports detected
usb 1-1.1: new high speed USB device using orion-ehci and address 4
usb 1-1.1: configuration #1 chosen from 1 choice
scsi1 : SCSI emulation for USB Mass Storage devices
usb-storage: device found at 4
usb-storage: waiting for device to settle before scanning
scsi 1:0:0:0: Direct-Access     Generic  External         2.08 PQ: 0 ANSI: 4
sd 1:0:0:0: Attached scsi generic sg0 type 0
usb-storage: device scan complete
sd 1:0:0:0: [sda] 488397168 512-byte hardware sectors: (250 GB/232 GiB)
sd 1:0:0:0: [sda] Write Protect is off
sd 1:0:0:0: [sda] Mode Sense: 21 00 00 00
sd 1:0:0:0: [sda] Assuming drive cache: write through
sd 1:0:0:0: [sda] Assuming drive cache: write through
 sda: sda1
sd 1:0:0:0: [sda] Attached SCSI disk
usb 1-1.2: new high speed USB device using orion-ehci and address 5
usb 1-1.2: configuration #1 chosen from 1 choice
scsi2 : SCSI emulation for USB Mass Storage devices
usb-storage: device found at 5
usb-storage: waiting for device to settle before scanning
scsi 2:0:0:0: Direct-Access     Generic  External         2.08 PQ: 0 ANSI: 4
sd 2:0:0:0: Attached scsi generic sg1 type 0
usb-storage: device scan complete
sd 2:0:0:0: [sdb] 1953525168 512-byte hardware sectors: (1.00 TB/931 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 21 00 00 00
sd 2:0:0:0: [sdb] Assuming drive cache: write through
sd 2:0:0:0: [sdb] Assuming drive cache: write through
 sdb: sdb1
sd 2:0:0:0: [sdb] Attached SCSI disk

And I was able to mount an NTFS formatted drive (using a 2.6.30.2 kenrel with ntfs-3g).

It's the closest I can get to the hardware you describe.

[c128]

Thanks very much for trying that - gives me some confidence that these slightly "odder" USB devices will work in my Sheevaplug set-up.

I think I might have changed my plans a little though...  As one of my drives has recently died, I think I might use the remaining 3 500GB individually through a hub, and then use them distinctly - one for music/documents/pictures, one as a nightly back-up of that, and one for general use (not backed up).  That'll give me a 1TB of overall storage with the bits backed up that I'm worred about.

With the above in mind, what would be really nice would be a compact USB enclosure that took 3 or 4 individual drives, had a single PSU and actually included a "proper" USB hub to make each drive accessible separately...not found one yet though  .

[NewIT_Marcus]

I said hub "of sorts" because it doesn't allow for the range of devices that a regular hub would; rather it is fixed to one or two hard drives. I'm not sure if there would be any other (significant) differences.

So the question becomes, I think, how many drives does the host see when the SAT354OU2E is connected. This offers a hint (from the manual):

Troubleshooting
Only one drive shows up over eSATA
If only one of the installed hard drives is visible on the computer when
connected over eSATA, ensure that the eSATA port on your computer
system supports Port Multiplier technology.

On the one hand, it certainly implies that you may (should) see multiple drives. On the other hand, it also implies that you might not be able to. I would think that you should be OK for USB, since it is mature.

[c128]

On the one hand, it certainly implies that you may (should) see multiple drives. On the other hand, it also implies that you might not be able to. I would think that you should be OK for USB, since it is mature.

mmm...I take your point.  I had assumed that what you saw with this original enclosure was a single "entity" based on all drives combined but, if not, then this would still be a possibility.  I'll do a bit of digging and maybe drop Startech a line.  Thanks.

[c128]

I've dropped Startech support a line to see what they say about individual drive access over USB.  They do flag Linux as a supported OS, so I'm guessing that their support will at least be able to comment in this
area.

Whilst having a dig about, I also stumbled across two other possibilities.

There's the IcyDock MB561US-4S, very similar (if much more expensive), enclosure:


http://www.icydock.com/product/mb561us-4S_frame.html

Now...there are quite a few reviews of the above about (e.g. http://www.pcreviewonline.com/reviews/hardware/icy_dock/icy_dock.html) but, unsurprisingly, most concentrate on its eSATA ability; neither the reviews nor the datasheet really clear up how the USB interface works with regard to invidual drives.

Cheaper, and looking better build quality than the Startech (at lest, from the photos) is the Edge10 DAS400:

http://www.edge10.com/digital_storage.php

Seems to be available for about £100 but, again, Linux compatibility in general (Sheevaplug aside) looks a little uncertain, although I did find this promising post:

http://www.readynas.com/forum/viewtopic.php?f=24&t=25371&start=0

[c128]

So...a bit of an update on this.

I got a reply from Startech, and the SAT354OU2E only works as a combined device, therefore any drives are not accessible individually.
However, I also got a reply from edge10 about the (cheaper) DAS400 - although they dodn't explicitly flag Linux compability, the support chap said it basically worked as a straight USB mass storage device, with combined/separate operation toggled via DIP-switches on the unit.  So, he couldn't see any reason why it wouldn't work, and...it does   .

Code: [Select]

[    3.870000] scsi0 : SCSI emulation for USB Mass Storage devices
[    3.880000] usbcore: registered new interface driver usb-storage
[    3.880000] USB Mass Storage support registered.
[    3.890000] usb-storage: device found at 2
[    3.890000] usb-storage: waiting for device to settle before scanning
-snip-
[    8.890000] usb-storage: device scan complete
[    8.890000] scsi 0:0:0:0: Direct-Access     Century  EX35SW4_SB4-A    0100 PQ: 0 ANSI: 5
[    8.890000] scsi 0:0:0:1: Direct-Access     Century  EX35SW4_SB4-B    0100 PQ: 0 ANSI: 5
[    8.900000] scsi 0:0:0:2: Direct-Access     Century  EX35SW4_SB4-C    0100 PQ: 0 ANSI: 5
[    8.910000] scsi 0:0:0:3: Direct-Access     Century  EX35SW4_SB4-D    0100 PQ: 0 ANSI: 5
[    8.960000] Driver 'sd' needs updating - please use bus_type methods
[    8.980000] sd 0:0:0:0: [sda] 976773168 512-byte hardware sectors: (500 GB/465 GiB)
[    8.990000] sd 0:0:0:1: [sdb] 976773168 512-byte hardware sectors: (500 GB/465 GiB)
[    9.000000] sd 0:0:0:2: [sdc] 976773168 512-byte hardware sectors: (500 GB/465 GiB)
[    9.010000] sd 0:0:0:3: [sdd] 976773168 512-byte hardware sectors: (500 GB/465 GiB)

I'm currently ext3 formatting the drives, and all looks well - my 500GB drive that had "failed" had actually just fallen out of my old machine's Intel Matrix RAID (a frequent occurence, not necessarily indicating a bad drive   ) and so I now have 4x500GB drives in the DAS400.  The only caveat is that I'm not sure what the spin-down situation is with these units, so I'm suspecting "none".  They do go into a low-power mode when not connected to an active USB host, but with the Sheevaplug that basically means it's connected all the time...I'll keep an eye on it and see what happens.

[NewIT_Marcus]

spin-up issues have been the subject of several threads at plugcomputer.org forum.

Thanks for the update.