Backup speeds dropped dramatically after upgrade

[Heather_Cochran]

We upgraded a customer to Backup Exec 11D from 10 last week and our speeds dropped from around 1000mb/m to 120 mb/m consistantly. After monitoring the server last night and this morning I see a 3 second read from the drives (tested this on Local SCSI and the FC SAN drives) about every 85 seconds and the byte count goes up on the backup job.

We have installed all hotfixes, removed and readded the tape device from backup exec, we tested throughput on the tape as well as the SAN and both are delivering greater then 2Gbps reads and writes to the server.

I've seen reports of others having similiar problems but no fixes. Has anyone found a fix for this?

[Philip_Pearson]

I read on a tech note about the block size being appropriate for the tape unit. If it is the wrong size it will slow down the backup. May be worth looking at what is recommended for your tape library and checking that it is set correctly.

[DanielBickford]

Heather,
Phillip is corect, block size can potentially have a significant effect on throughput. However, you must be aware that although larger block size can significantly improve your throughput, if you set the block size to a larger number than the tape drive can handle, you may not be able to restore data from that tape. Just makesure you run at least a couple of test restores after changing the block size.
It is a good idea to check with the manufacturer before making a change to the block size.

-Daniel

[Jorgen_Persson]

Shouldn't the Symantec provided tape driver set this to a correct value? How come it worked fine in V10 but suddenly in V11 we manually have to find the correct setting. Am I the only that have a problem with this? I might add that all my backups are runing less then half the speed sense I upgraded, both the B2D and B2T.

[Heather_Cochran]

I found the problem. The FC HBA the tape was on had a driver update available. I also reluctantly upgraded the firmware on the Sony SDZ-130 Tape drive. This fixed the problem. It stil isn't as fast as it used to bewith 10D but it is acceptable now.

[Corey_Wilson]

Hi Jorgen,

You are not the only one that has a problem with this. Ethically there have been a lot of small glaring problems like this with this version that in my opinion should not be on an enterprise gade backup product. Heck, on any backup product for that matter. I am glad to see Symantec is finally providing some appropriate support to help rectify these issues albeit much later then should have occured to begin with.

I hope they have learned their lesson. You cant fault the new north american based support technicans frequenting this forum now, but Symantec themselves needs a good swift kick in the backside, especially considering the product, agents, licenses, etc are not cheap.