Dramatically slower backups with new LT05 SAS drive

[UCSC-DCal]

Hi,

While I am sure that this has been asked many times over, I cant find an answer that works.

I have BE 2012 Server Version 14.0, Rev 1798 (64 bit) runing on WinServer2008-R2 with 8GByte.

I had been running a Qualcomm LTO4 SCSI drive up until about 3 weeks ago, getting anywhere between 1500 and 1900 MB/Min speeds. My LTO4 drive failed and I replaced it with an HP-LTO5 SAS drive, and the best I can get out of it is approximately 600 Mb/min speeds. So what used to take 6hrs to back up, is now taking much more then over night, close to 18hrs, with Verify set.

The BE software was not reinstalled, I just deleted the old SCSI device, and add the SAS box. I let it install the Symantec-BE drivers.

I see many threads on the Drive devices properties in different ways. Can anyone share the location of best practices settings for my configuration?

Thanks to all in advance!

[CraigV]

Hi,

Have you considered removing the tape drive from Windows and BE, restarting the server and reinstalling the Symantec drivers via tapeinst.exe?

Also make sure that the SAS card used is supported for use with tape drives, and is not a RAID controller which isn't. You could consider upgrading the firmware on the SAS card and tape drive (via HP Library and Tape Tools) to rule that out.

Thanks!

[lmosla]

Even though it is for a lto4 tape drive, take a look at pkh's article on tuning a tape drive. https://www-secure.symantec.com/connect/articles/tuning-my-lto4-tape-drive

hope this helps 

[pkh]

Yes.  You should increase the buffer and block sizes.  The default 64k buffer and block sizes are too small.

[UCSC-DCal]

Hi All,

First thanks so much for all the help, unfortunately, I still have not the speed for backup like I used to have with the SCSI drive.

I tried adjusting one at a time adjusting Block, Buffers and High Water counts, and nothing made much difference. I actually reinstalled clean  BE 2012, wondering if there was junk left over from the original install with the SCSI LT04 box. No difference, still averaging 650 MB/Min, which is just not acceptiable, as I have a AutoCAD server with just under one TByte of files, this is taking 34hrs to do a full backup. At my former speed of 1800 MB/Min I could back up this data in about 7 hrs.

I am now looking at the SAS card itself. Research is showing that cheaper cards, which is my bad choice, carry much slower possible speeds. Does any body know this to be true, and could be causing my issue?

Thanks again to all...

[CraigV]

...never heard of that, but it could be anything from outdated drivers or firmware, to card incompatibility with the drive itself, to an incorrect card, ie. RAID controller instead of SAS card supported by the tape drive.

Thanks!

[UCSC-DCal]

Well... checking the card (which is a non RAID, single SAS channel only card) specs it is rated for up to 6Gb/s. The Symantec drivers had no problem finding and communicating with the LTO5 deck through the card.

I remember having this issue before, when I first got my LTO4 drive, but then I was under Symantec maintenance, and was able to have a support session with someone that did some probing, and fixed things in a hurry. Before I close this thread down, does anyone roughly know what a support call costs these days for this Backup issue?

Again.. thanks to all.

[CraigV · Accepted solution]

...you might want to contact Symantec and ask them.

Thanks!

[UCSC-DCal]

Thanks @ Craig.. I would admit to being lazy about the researching the cost, having spent more time then I cared to on hold with them, when I had maintenance. Great when I got someone, but, a bit of a maze. But that looks like what I will be doing.

Thanks!