bizar problem: we use legato 5.1 f

[ukraine12]

bizar problem: we use legato 5.1 for unix and nt severs.
we backup over 100mb full duplex connections. all our settings are good. it happens that a backup is running at 5mb/sec for some hours, then suddenly the speed drops to 300kb/sec for a couple of hours and then picks up again to the 'normal speed'. we have had it checked and can't find a thing, we had scsi card replaced, didn't help. we use a stk robot with 12 drives and 5 scsi cards to it. the server has got 5 different network cards, all the clients are configured correctly and there is no heavy load on the machine. Even if we kill all the backups but the one with the slow speed it doesn't work. there is also not a lot of activity on the client side.
what is going wrong?

 

[mercenary]

Is it possible that you are backing up a lot (read, thousands) of little tiny files at that time? Check the filesystem and see what the makeup of your files looks like. It sounds like everything is working fine, since the backup speed is cruising nicely for the beginning and end of the job. We have a similar problem backing up one host out of 150 on the same network, but just on one filesystem loaded with tiny files. The other filesystem runs at 5+MB/sec.