I’m having a perplexing throughput issue with my tape backups. Every two weeks (on a Tuesday for the past two months) my tape backup throughput decreases dramatically – from 1,360 MB/min to 130 MB/min. The speed decrease happens regardless of the source of the backup – over the LAN or running a duplicate job where the backup-to-disk folder is stored on the backup server hard drive. This situation does not impact the speeds of disk-to-disk backups. The only way to resolve the issue is to reboot the backup server. Below is my configuration.
Dell PowerEdge 2850
Dell PowerVault 124T LTO-3
Adaptec 39160 SCSI adapter
Windows Server 2003 Std x64 SP2 fully patched
Backup Exec 2010 fully patched
Troubleshooting steps I’ve taken
contacted Symantec who had me run various diags
contacted Dell who had me upgrade the firmware for the tape/autoloader
checked to make sure there are no scheduled tasks running during this time
checked Task Manager for processing consuming CPU or generating lots of I/O – none found
compared running processes to server after reboot – no differences
rebooted server for several consecutive days to see if it would extend the interval – it did not
verified all the drivers were at the latest levels – tape, autoloader, SCSI adapter
checked Windows Application and System logs for errors – none found
checked tape autoloader logs for errors – none found
checked tapes for errors – none found
Anyone have any ideas what could be causing those or what other steps I could take to troubleshoot the problem?
We need to restart the whole server. Dell may have isolated it to a hardware issue. The condition raised its ugly head today. Dell is running ITDT diags against the tape drive. The performance test is taking an unusually long time. Hopefully the logs will tell us something when the test finishes.