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SAS LTO4 Autoloader support


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Any eta on supporting SAS devices? We bought a LTO4 library that uses SAS. Initially we contacted EMC about purchasing the drive and was told it was supported but it wasn't explained that did not include SAS drives. I realize the list is out there but since we were contacting directly we didn't check. So now we have a 7.6 system that looses the library on a consistent basis and jeopardizes our backups. We opened a case and were told you were working on driver update? I'm hoping this will be resolved quickly or we may need to look at another product thats supports SAS.

 

Thanks

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  • 1 month later...

PLEASE, AN UPDATE ON SAS SUPPORT AND/OR WORKAROUNDS!

 

Hmmm, I thought this would be a hotter topic. I will volunteer my problem: A Dell Powervault 124T 16 tape changer with a Quantum LTO4 SAS mechanism. The server is a Dell PowerEdge 840 with a Dell SAS 5/E controller. (PCIe x16)

 

So, this is intended to be an upgrade from our older PV124T/LTO3 SCSI based unit. We need the increased speed and capacity at our primary site, the older unit will pass to a satellite location.

 

We use a Disk-Disk-Tape method, putting locally stored RDB files directly to tape at night for maximum streaming.

 

Result 1: The drive and changer are visible with in Retrospect, all looks OK.

 

Result 2: With a tape in the drive, backing up RDB files is either exactly the same, or possibly slower than the older drive. We ran the test during the day, so I can't be too scientific about the results, but my gut tells me I'm in trouble now.

 

Result3: The changer shows tapes and barcodes, put will not play with the drive at all. No drag and drop. I can use the drive's web GUI to move tapes around, making it a very expensive single LTO4 drive.

 

We have reverted to the old drive for now. With EMC's rollout of Retro8 for Macintosh, I am led to believe there is a commitment to this product, so if it's not going to be years, please give an ETA for drivers for what I have to believe will be mainstream products.

 

And... are there any workarounds to the performance issues for the SAS drive itself? I think I read something in this forum about registry weaks for the SCSI/SAS card drivers, but didn't really get any explicit guidance.

 

Thanks in advance, and don't make me leave the Retrospect fold. I'm too old to recreate all these scripts!

 

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Update and apology!

I decided last night to give it another try. This time I noticed that the latest Retro release (.123) included a driver update not available to the one earlier version we were running. When I found the release notes for the driver/hotfix, I saw that the PV124T SAS was explicitly mentioned. And lo, the changer now works as it should.

 

Questions remaining:

- We are still running a full backup on the SAS LTO4 and once done will compare speeds with the previous nights backup on the SCSI LTO3. As of right now the speed looks to be near the same. Is this a throughput limit from retrospect, or might it be something that can be tweaked? For full disclosure, I still have the Adaptec 39160 card in the server, could that be competing for resources?

- A niggly question about Retrospect and changers: If a backup finishes a tape and needs a new blank tape, it will always start at the highest numbered slot and work backwards. I would think for organization you would want it the other way around. Is this changeable, or is it a function of the hardware?

 

Thanks in advance, we're making progress!

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