New installation of Tandberg LTO-6 + LSI Logic 9201 16e SAS card - slow performance. Wrong SAS card?

[imekul]

I just installed my first LTO-6 drive and SAS card on a Windows Server 2016 Essentials system. The drive is an external Tandberg LTO-6, and the card is an LSI Logic 9201 16e. From my interpretation of the Tandberg compatibility matrix, I think the card is supported.

I have the drivers installed for both the card and the drive, and I have also installed the HPE Library and Tape Tools that Tandberg provides on its download site.

HP L&TT is able to detect my drive, and I can run it through the various tests. All the tests pass, however I get a note saying "Drive performance is severely limited. Check HBA and cable configuration. Check that you have an appropriate HBA at www.hpe.com/go/connect and that drivers are correctly installed. See www.hpe.com/support/pat for more information."

I've tried plugging the SAS cable into a different port on the LSI card, but that doesn't seem to have changed anything.

I then formatted a tape for LTFS using the LTFS Configurator tool that Tandberg gives out. Using Windows Explorer to drag and drop a test folder onto my tape drive, my transfer speeds will top out at 170 MB/s but then will slow to almost nothing, before climbing back up to the top speed. During this time I can hear the tape drive whirring at different pitches, as if it's slowing down and speeding up as the transfer speed changes. It will do this over and over, alternating between fast speeds and super slow speeds, for the duration of the transfer.

I should point out that using HD Tune to measure my drive performance, that drive typically shows read speeds of 170 MB/s.

So it seems that something is not right. However, I'm totally new to the world of LTO and don't know what to expect so I'm not totally sure where to look. I have a hunch that the culprit would be the SAS card itself, as I've seen people recommend ATTO cards, and I've noticed they happen to be about 10 times more expensive than my LSI Logic. ? However, as this LSI Logic 9201 16e appears to be a recommended card by Tandberg, I thought it might do the trick.

I also tried this drive/SAS card combination in a different computer and had pretty similar results, including the warning in L&TT about the drive performance being severely limited.

With all of that info, can anybody help me out? Does it sound like I'm barking up the right tree in terms of the SAS card being the culprit? Or are there some other troubleshooting steps I can take?