Slow backups

[Viking698]

Ok running backup exec 2010. using a scalar 24 tape library. Was using LTO1 tape for the backup. Switch(finally) to LTO2 tape for the backup. What I'm getting is the backup went from 1,300MB/minute to 149MB/minute.

Anyone ever seen this? Has me stumped.

Viking

[Hemant_Jain]

It would also depend on what you are backing up. If remote backup, it would depend on network.

Thanks

[Ken_Putnam]

Frm the poperties page for the new drive, verify that both Single Block options are DISABLED.   what are the other settings? 

[Viking698]

No it is not a remote backup. The tape library is connect to the computer via scsi cable.

The drive is not new, the only thing that has changed is the tapes. Config is as follows

Enable compression = check

Block size = 64k

Buffer size = 64k

Buffer count = 10

High water count = 0

Read single block mode = unchecked

Write single block mode = unchecked(was checked)

Read scsi pass through mode = unchecked

Write scsi pass through mode = checked

Still has me going huh.

Thanks for all your help.

Viking

[Ken_Putnam]

The drive is not new, the only thing that has changed is the tapes

Ok, that makes it even more strange.   Everything looks good you might want to increase the buffer size to 128 or 265 if you have plenty of RAM on this system, but that won't make a huge difference

[pkh]

What happens when you switch back to LTO1 tapes?

If you do want to tune your buffers, do read my article below first.

https://www-secure.symantec.com/connect/articles/tuning-my-lto4-tape-drive

Although it is for LTO4 tape drives, it may relevant to you.

[CraigV]

Hi Viking,

When you replaced the drive did you perhaps consider updating your drivers for BE 12.x, and then install them using the Device Configuration Wizard from within BE?

It IS possible that BE isn't fully utilising the better speed of LTO2. That said, I trust you aren't writing to LTO1 tapes...?

Thanks!

[Colin_Weaver]

Did you replace the drive or just the tapes used in the drive?

As if just the tapes I would suspect a compatibility issue between the tapes and the drive.

[Viking698]

I thanks all for the replies.

I have yet to go back and test the LTO1 drives. I will be doing this on monday to see what happens.

Yes I just changed the tapes nothing else. That is why it is driving me nuts.

I will try to reconfigure the tape drives and see what happens over the weekend.

Ok thanks all

Viking

[Viking698 · Accepted solution]

Ok manage to update all the tape drive drivers with no effect same problem as before.

I did retest my old lto1 tapes and once again they work perfect. After much testing it does appear I have a bad batch of tapes. It was one of the only things I did not even think about.

Viking