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?