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MSL5026 SDLT Problem

Arresto Ario
Occasional Contributor

MSL5026 SDLT Problem

Dear expert,

Need your help to clarify about MSL5026 SDLT
We have upgraded our system from Windows NT4.0 to Windows2000 server, we used Legato Networker 6.2
We don't know why suddenly the backup speed reduced from 10-15MBPS to 550-700KBPS
Is there anybody knows why could it happened to our system?

thanks and regards,

Vincent Farrugia
Honored Contributor

Re: MSL5026 SDLT Problem


It could be that your backup software is still on its default block size after upgrading to windows 2000. The block size for SDLT should be 32k. If this is smaller, then that is why you have performance problems.

Tape Drives RULE!!!
Ross Humphryes
Frequent Advisor

Re: MSL5026 SDLT Problem


You'll find that the problem of performance is resolved if you upgrade the Compaq drivers. Possibly you SCSI driver is and old version and this needs updating.

We use Legato and MSL5026 on W2K and we had this problem. We had to update the drivers, install hotfixes and make a registry hack to make this platform reliable.
Get in my belly
Frequent Advisor

Re: MSL5026 SDLT Problem

I have the same problem with W2k. However performance degradation has random pattern. I mean, that same file, starts backing up at 10MB/s, in the middle drops to 600KB/s (I see traffic on the SAN switch), after while it ends up with "Medium error", or restores to 10MB/s.

2Ross: what registry hack have you implemented ?
Ross Humphryes
Frequent Advisor

Re: MSL5026 SDLT Problem

Hi Saulius

Sorry I'm late at getting back to you.
If your Tape Library is SAN attached that just makes things more tricky to analyse because now you have the FC-HBA driver, firmware to update as a first step and then the FC-HBA config to examine, the NSRs or MDRs to update and examine, the switches to update or examine... to be honest I'm not a SAN expert.

If you still have the problem you needs to ensure you have the latest SCSIPORT.SYS update from Microsoft in place. You need to update your FC-HBA driver and firmware.

Then make sure your Tape and Library drivers are up to date. Make sure the firmware on the Library and tape drive is up to date.

Make sure the fibre channel switch ports are fixed (not auto) and match the speed that your FC-HBAs are running with.

If the memory and CPU status on both backup client and host are in good shape, the file system you are backing up is healthy and you still have the problem you need a SAN expert to examine the config.

Better late that never !

PS. The patch I spoke about on W2K was one to allow more simultaneous sessions to run, this addressed the desktop environment on the backup server and not performance.
Get in my belly