Backup Exec 12.5 backup speed issue

[Dean_Higgins]

Hi guys, allow me to explain my situation here.

I'm running server backup daily with BE 12.5 and concern whether the backup speed is proper. I read around and found out that slow speed may relate to SCSI cable, driver, etc...

The situation:

1. Tape drive is LTO 4, tape LTO 4 800GB/1.6TB compressed.
2. Backup size is currently 1.1TB and 3GB+ increase every day.
3. Final backup speed varies every day between 1GB-1.7GB per minute.
4. Elapsed time varies between 11-17 hours depends on speed.
5. Settings are default from our admin. Block size 64KB, Buffer size 64KB, Buffer count 10, High water count 0, Write single block mode ON, Write SCSI pass-through mode ON.
6. No admin access to modify driver or do update. Configuring BE settings is possible. Hardware (cable) job is possible but risky since I can't make a mistake here.

I assume my backup speed is slow and could be improved. Having issue especially if the backup failed and have to re-run it during office hours which won't finish on time before the next backup.

I'm not really clear on what affects the backup speed since the results every day is always vary.

Please let me know if you have any advice on what to try, either hardware/software/update/settings/etc... or maybe if the speed actually is already acceptable.

[sksujeet]

Speed is always depends upon the network bandwidth at the time of bacup. As you said that you are getting around 1gb to 1.7 gb/ minute looks good to me. This is the normal speed that I have seen in the same configuration. You could do couple of things to make sure every thing is good. 1> Make sure you have symantec drivers loaded 2> Make sure RSM service is disabled 3> All the scsci and controllers firmware is upgraded to latest. 4> You can disable the compression and check if it make a difference. I have seen in the past the compression reduces the throughput rate. You can just give it a try as disabling compression will not be a good idea as you might be wanting the data to be compressed. 5> Do not change the drive properties like block size and water mark as it might cause problems

[teiva-boy]

As it pertains to #5, I do not agree with sazz.  The statement is one that Symantec documentation states, but in the real world, this does NOT apply.

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

There more to tuning then just the above, but this will get at least the tape performance perfected.  Then there are other things that can be done with disk defraggers on the clients, jumbo frames, backup to disk, etc..

[pkh]

Changing the tape drive's block size and buffer size is at the same or greater technical complexity as editing the windows registry.  The necessary precautions should be taken.  If you know what you are doing, you will be fine.

[Dean_Higgins]

Is it safe to ignore the warning coming from increasing block size? What does "not be able to restore data" exactly mean?

"If you increase the block size, you may not be able to restore the data. Make sure your backup is verified."
 

[pkh]

No.  When you change these parameters you should ALWAYS do very thorough testing to ensure that you can read back the data.