Slow Backup Performance

[Mike_Bowden]

Hello,

I just upgraded our main file server with a larger hard disk and a faster network connection. I also added a gigabit network card to our Backup Exec 9.1 server. Both of these computers are plugged into the same gigabit switch, and the switch management shows both systems connected at 1000/full.

However, during the nightly backups, the backup speed averages about 130 MB/Minute. According to the specs on our tape drive, it should be backing up at at least 35 MB/Sec (or 2.1 GB/Hour). And these are the low-end specs.

I have tried backing up large files on the local backup system to see if it was a network issue, but it runs at the same speed. It is getting to the point where the backup barely finishes verifying from the night before when it is time to leave for the night. (The full backup/verification of about 83 GB of data takes around 19.5 hours).

Our tape drive is a Dell 110T LTO-2. We are running Backup Exec 9.1 on an XP SP2 station. Backup Exec is the only application we run on this computer. I have upgraded to the latest drivers from Dell, but this did not help.

Please tell me if I am overlooking something obvious, but the way I see it, our entire network should only take less than an hour to back up, and then probably the same amount of time to verify.

[Mike_Bowden]

Correction above: at 35 MB/sec it should be backing up about 2.1 GB in a minute, not an hour.

[Ken_Putnam]

From teh devices tab, right click the drive\properties

What are the settings for

Block Size
Buffer Size
Number of Buffers

[Mike_Bowden]

Block Size: 64K
Buffer Size: 64K
Buffer Count: 10

And thanks for the quick response!

[Ken_Putnam]

Those settings should work OK

You might try setting buffer size to 128K just for grins

If you listen while a backup is running, does it sound like the drive is stopping and starting? or does it sound like it's continuously streaming?

If you compare the number of errors before and after a backup, is it generating a large number per run?

Do you have any mfg diags you can run against the drive?Message was edited by:
Ken Putnam

[Mike_Bowden]

Interesting question.

It DOES seem to stop-and-start, but I was assuming was normal operations. There is a green activity light on the front of the drive. When it's writing, it seems to be solid green, but once a minute or so it flashes green and I can hear the tape mechanism stop and start. This drive is only about 6 months old, by the way.

I don't have and diagnostic tools for the drive, and I didn't see any available on their web site.

[Ken_Putnam]

If you have plenty of RAM on the media server you could tweak tha buffer settings a little

I assume that 64K is the max block size availalbe? if not set it to what ever is max

Set buffer to 256 if possible

Set number of buffers to 20

if the OS can keep the buffers full of data, the tape drive should write in one continuous operation. If it's stopping and starting, then the buffer is probably emptying

[Mike_Bowden]

I figured it out. There was an updated Adaptec Driver on Dell's website. As soon as I ran it I was getting 1.5 GB/Minute speeds.

Thanks for all the replies, Ken.