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I have a Dell T710 with Seagate Cheetah 15k.7 SAS disks. If the T710 motherboard dies, I'll need to resort to one of my nightly off-site backups and salvage the journal/logfile from the SAS disk to bring the backup bang up-to-date.

I need a way of reading the healthy-but-inaccessible SAS disc that does not depend on the only SAS-capable machine I have to hand.

So I bought:
SAS to SATA Adapter
and:
USB 2.0 to SATA Adapter with Power
...so that I could read the SAS drive via USB.

I can plug it all together just fine. The chain looks like: USB -> SATA -> SAS. But the drive does not spin up and the computer doesn't even acknowledge anything being attached by USB.

Is there a cheap external enclosure I can buy for SAS drives? I can't believe these USB to SATA adapters are everywhere but the USB to SAS adapters are almost non-existent...

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2  
That drive can hit up to 16 watts of power usage.. I would not trust that USB adapter to maintain that kind of load. –  pauska Apr 4 '12 at 20:13
1  
considering the price of a SAS drive and the target customer, it doesn't really surprise me that there aren't any USB adapters around for it. –  Lucas Kauffman Apr 4 '12 at 20:15
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It would appear you are not fully conversant with the concept of backups. –  John Gardeniers Apr 4 '12 at 22:21
    
@pauska - the SATA adapter has a 2amp power injector. –  dave Apr 5 '12 at 10:44
    
@JohnGardeniers - the data is backed up nightly and off-site (although admittedly not mirrored). If the Dell T710 dies some hours after the backup, I need to patch the live journal file from the dead T710 onto one of the backups. But how do I read the SAS disc containing the journal? –  dave Apr 5 '12 at 10:53

2 Answers 2

Your SAS to SATA adapter isn't a protocol translator, just a pin to pin adapter. It won't let the USB to SATA adapter speak to the SAS drive in any language other than SATA... which it won't support. So you won't see anything happen.

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SAS is largely an "enterprise" tech whereas USB is most definitely not (at least as far as storage goes, anyway). I'm guessing this is why you haven't found any suitable adapters.

That said, you're going about this the wrong way. With a good backup regimen, you dont need the original hardware. So, get a good backup system in place and this issue is resolved.

As an aside, your proposed solution (USB SAS enclosure) only protects against a very small subset of failure modes. How do you propose you'd recover in the event of:

  • fat-fingered command that deletes a bunch of data
  • RAID card nastiness that corrupts data
  • theft
  • disk failure
  • nuclear fallout

To recover from these, you need a real backup solution, and preferably one that moves data off-site.

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+1 for backup rather than "Rube Goldberg " device –  Dave M Apr 4 '12 at 20:57
3  
@DaveM But Rube Goldberg devices are FUN! :) –  EEAA Apr 4 '12 at 21:00
    
@ErikA - thanks for your input. The data is backed up nightly and off-site (although admittedly not mirrored). If the Dell T710 dies some hours after the backup, I need to patch the live journal file from the dead T710 onto one of the backups. But how do I read the SAS disc containing the journal? –  dave Apr 5 '12 at 10:59
    
@ErikA - just to answer your 'asides', I think these are dealt-with thanks to the periodic off-site backups. The specific scenario I am trying to cover is when the SAS disc is fine but the Dell T710 (for whatever reason) will not read it. (Maybe the T710 motherboard is broken; maybe Windows won't boot). I need a way of reading an SAS disc that does not depend on the only SAS-capable machine I have to hand. –  dave Apr 5 '12 at 11:08
    
I need to RMA a SAS disk, and would definitely prefer to wipe it first. I may get a SAS to SATA adapter for this purpose. If a laptop had an esata connector, it may help in your scenario too. –  northben Jan 11 '13 at 15:24

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