SAS Controller Support & Cable for SAS Tape drive

[justinz]

This new topic because existing threads are so old...

EDIT:

I'm changing this post & title because I gained some sensibility about SCSI+DDS, and now am intent on using a SAS LTO-5 tape drive, connected to a PCIe 1x card. Unfortunately my knowledge of SAS is very limited..., I'm looking to buy an ultra-cheap noname SAS card and attach it to an HP Ultrium 3000 tape. Adaptec ASR-6405E is a RAID card, and "Mini SAS SFF-8087 SATA3.0 6Gbps Adapter Card Har X5O1" is ... I don't know what, but if it works, then it's cheap and simple, with just a mini-SAS connector. Of course, not being from a big-blue manufacturer like IBM, LSI, or Adaptec, support for Retrospect may be completely missing.

So if a controller has an internal mini SAS port, do I look for a cable: INTERNAL mini-SAS to EXTERNAL mini-SAS?--if my tape drive is external with a SAS connector. Or do I look for a cable INTERNAL mini-SAS to four disk-SAS connectors, and only use one of the legs?--if my drive is internal.

I supposed I'll experience a major wake-up call when it come times to actually design a strategy with only a single tape drive. I admit this is just the nerd in me that wants to waste my time doing this. Oh well.

----

Originally I had written: (short version) -- "I'm not sure if I should look for a SCSI controller that's 'known good' or take a chance with a random card that fits my host PC. In this day and age of Win10 (vs back in the early 2000's), are more SCSI cards working due to generic driver modes, or does support need to explicitly exist inside Retrospect software for each brand & series?"  .... effectively I had asked if an IBM 5785 PCIe x1 Neo 4p HiPro N11702 SCSI controller (which is possibly an obscure card) would work on Windows 10 for a DDS library. Retrospect support indicated that shouldn't be too worried about the card make/model under Windows10.

But now realizing how old and slow DDS3/4 will be, I'm no longer nostalgic for my old HP DDS4 library.

Edited May 6, 2022 by justinz
Changed intent

[Nigel Smith]

On 5/4/2022 at 1:35 PM, justinz said:

I'm looking to buy an ultra-cheap noname SAS card and attach it to an HP Ultrium 3000 tape.

Retrospect shouldn't care, as long as the card works. Windows and your HP drive may have other ideas, so aim your compatibility checks in those directions.

Where that theory breaks down is that RS can pump a lot of data through a card at speed, and that can reveal flaws in card design,ompatability. To an extent you get what you pay for... If your data is valuable enough that you're going to spend time backing it up, perhaps it's worth splashing out a little?

[justinz]

I keep telling myself -- "Just get a 12TB hard drive"...  But then I come around to thinking that a tape can be removed from the system, so in the event of corruption from virus/malware/ransom then I can rebuild.

And about the 1x PCIe part -- I had wanted to keep to an ultra small server that I use for a number of other services... Now, HP lists the EliteDesk 800 G1 USDT mPCIe as 2.0, so 1x should be fine for an LTO5. (I have an MXM graphics card installed, and CPU-Z reports that is running at 3.0; so I imagine that's a separate bus from the mPCIe slot). I realize that LTO5 (280MB/s) is pushing past 1x @ 1.0 speeds, particularly if compression is used, and LTO4 is only a little slower at 240MB/s. This is telling me to abandon the idea of miniPCIe-to-PCIe_1x-to-PCIe SAS controller if mPCIe is not running at least 2.0 (with yet-unknown SAS controller) at 500MB/s per lane. (And hopefully the mPCIe isn't whitelisted as Lenovo's are).

On a side note, worth mentioning -- I was able to use PCIe-1x-to-PCI_bridge adapter to configure an old PCI (not express) Adaptec AHA-2930 SCSI card and exercise some old HP DAT 6/40 (DDS3) and DAT 6/72 (DAT4) libraries, under Windows 7 64bit. (This was just a little fun before I scrap these devices... eventually. I have dozens of DDS3 tapes, many new, ... just sayin').

Now as far as a single LTO tape drive (SAS) is concerned... What happens when grooming backups sets on LTO? Does it treat the tape like a filesystem, and it simply deletes data from the files--marks filesystem blocks on the tape medium as freed-up? So if I don't exceed the capacity of a single tape, I can leave one tape in the drive indefinitely, as if I were using a hard drive, but not thrash as disk-i/o access does?...  and set the retention/groom policy to keep to the capacity of one tape? ... Or perhaps do minimal tape changes, say a quarterly full or DR-image backup.

In reality my data isn't that valuable... just personal files and photos. But we all do so much paperless these days--I don't think anyone can really afford data loss.

[Nigel Smith]

On 5/13/2022 at 8:53 PM, justinz said:

Now as far as a single LTO tape drive (SAS) is concerned... What happens when grooming backups sets on LTO? Does it treat the tape like a filesystem, and it simply deletes data from the files--marks filesystem blocks on the tape medium as freed-up?

In theory it could, but I've never tried. If you're worried about HD thrashing, think how bad it would be for a tape, constantly spooling/respooling to find those gaps to fill!

If you want to do grooming and WORM (form ransomware protection etc), consider an HD for your "normal" backups and a regular copy from that set to a tape set for "permanent" storage -- disk-to-disk-to-tape. There's many ways of setting that up and you can adjust to suit your own schedule and retention policy. See the RS manual, particularly the "Staged Backup Strategy" examples.

[justinz]

RE: SAS controller for LTO-5 tape.

Can anyone suggest what's wrong here? I can see my HP Ultrium LTO-5 tape drive in Windows 7 Device Manager as "Tape Drives > HP Ultrium 5-SCSI SCSI Sequential Device", but not inside Retrospect. I've also installed the LTFS Tools, and configuration utility give me "No suitable tape drives found!" I installed the driver from HP's "cp049429.exe" set, which appears to support W2K through Windows10.

The tape drive is from a library sled that I bought used, because the external fan mount was bent, so it's possible the drive doesn't work. But I would expect it to at least be recognized by software apps. (Device manager sees it, and says it's working properly).

I'm using an Adaptec ASR-6405E SAS adapter. I selected this card because it was suggested in a Reddit post, and because it's PCIe 1x. (I'm just not content selecting the first card I find someone mentioning in forum; I want one that suits my needs--I don't need support for multiple chains of 8+ hard drives, doing RAID/etc, just one that supports a tape drive and is on the smallish side.)

What about LSI SAS 9211-4i? That's a relatively small card (not 1x). (I also tried a "Mini SAS SFF-8087 SATA3.0 6Gbps Adapter Card Har X5O1" from AliExpress, but tho the drivers installed without error, using that card I didn't see the tape drive in Windows device manager, let alone in RS.)

Any ideas?