backup of small files is slow

[Jeffrey Kuikman]

Hello, i have a problem with backing up small files.

HP DL360 2 GB mem
36 GB scsi disk mirror.
HP ultrium 960
LSI Logics scsi u320 166 Mhz card
Win2003 sp1
Veritas 9.1

I run L&TT sys pref tape tools test.
One big file 53 GB is done with 30 MB/s
big bunch of small files (60 KB) with 6 MB/s

Disk block size is 512 KB

Kabels are ok, termatation is ok. Drivers are updated, Hp softpacks are installed.
Anybody?

[Uwe Zessin]

It's a well-known problem. For all files, the disk drive needs to move the head between the filesystem meta-data and the user-data, but the head moves for many small files cause more 'lost time', which is not available to transfer data.

[Jeffrey Kuikman]

Even that much loss? form 30 mb/s to 6 mb/s..

Thinking out loud:
So they only way to solve this problem would be to make a sort of snapshot of the small files.
Like the OFO option does in veritas?!?

[Uwe Zessin]

A "snapshot" will provide you with a consistent view to the data - in other words:
if you do an online-backup, you don't see any user changes in you backup job that could cause inconsistencies.

It cannot cut-down head movements, but it is a "trick" to shorten the time of unavailability of your application.

[Jeffrey Kuikman]

Thats a good point. Oke well thanx for your help. Have a nice weekend.

[Richard Bickers]

The problem is fundamental unfortunately but fragmentation makes it worse. If you haven't defragmented your file system for a while you should do so. Having your small files broken into even smaller pieces can't help.

You can use HP LTT (www.hp.com/support/tapetools) to measure the read performance of your file system independent of your backup app (use system performance test - backup pre-test). You'll probably get the same answer but it's a handy test for experimenting and checking the results quickly.

The low performance won't hurt the drive too much - at least you've got the capacity of the 960.