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Slow backup throughput

Level 3

Our backup is currently running for nearly 17 hours while it used to take about 12 hours. The problem first occured after installing a batch of Windows updates. After uninstalling those updates, the performance never returned to "normal".

Last weekend we decided to take a dedicated server and reinstall our backup solution. The server which hosted Backup Exec originally was a relative old Dell Poweredge 4400 server which also hosted al lot of other applications like Symantec Antivirus, Microsoft SUS etc. etc.

The new enviroment consists of:
HP/Compaq Proliant DL380 G2
2x 1400MHz CPU
1536Mb RAM
2x 9,1 Gb 10K RAID1 for OS
3x 18.2Gb 10K RAID5 for Backup Exec
HP/Compaq Dual Channel Ultra3 SCSI Host Adapter (originally from a Proliant ML350)
HP/Compaq NC6136 1Gbps Fiber NIC

Tape Drive
Sony Storstation LIB-162 (library) with 2x AIT-3 drives
Drivers from latest driver pack from

Windows Server 2000 SP4 with all applicable hotfixes

Backup Exec
Symantec Backup Exec 10d with all applicable hotfixes
Remote Agents with AOFO
Exchange Agent

We have one central backup server which processes all our servers over a 1Gbps fiber network. I have split our daily full backup in two jobs: one consists of the system drives, system states etc. of all our servers (about 10) and one job for all our data (about 300Gb) which is located on a HP/Compaq Moldular SAN Array 1000 with two nodes running Windows 2000 Advanced Server clustering.

The job which processes the servers runs fine within a 7 hour time frame, the other job is running 18 hours with an average throughput of 300mbpm. It used to run over 500mbpm and took just over 12 hours.

I have updated the firmware and drivers for every device I can think of and installed all the hotfixes for both Windows and Backup Exec. The only problem I encountered there was with the SCSI card. Accoring to the HP System Management Homepage the SCSI card is a HP Dual Channel Ultra3 SCSI adapter but when I try to download and install that specific driver, Windows tells me that it is not the correct driver. If I ignore that warning and install it anyway, the card does not start after rebooting Windows and gives an exclamantion mark. When I roll back to the original Microsoft driver, the card is identified as a Symbios Logic 875SID, 2290x PCI SCSI Adapter.

Does anyone have an idea how I can increase the throughput of my backup?



Jeffrey Kusters
ING Assurantiekantoren
The Netherlands

Level 6

Please refer to the technotes given below.

(title) What Backup Exec settings can be modified to reduce the amount of time it takes for a backup to run

(title) How to correct slow backup performance, slow virus or pre-job scans, and agent initialization problems on fragmented Windows NT, Windows 2000, and Windows 2003 server partitions

Note:- if we do not receive your reply within two business days, this post would be assumed answered and archived.

Level 3
I had the same thing happen after a batch of windows updates. Have tried updating all the firmware etc. like you describe. Backups doubled in time frame to finish. Same amount of data- same number of tapes. Differences from your environment is that I'm using an IBM 3581 LTO-2 drive directly attached to server, OS = WinServer 2003.
Nothing in the settings of my jobs were changed from good backup day to bad backup day. Only thing that happened was a reboot of server that the windows updates asked for. The mentioned articles don't mean much in that case. If the settings worked one day they should work the next day.
I've been coming in to work at midnight since I can't do alot to the server during the day and halt work for everyone. Needless to say I'm tired and frustrated with this problem. Hopefully there is someone out there that can help us!!

Level 3
Do you know which Windows Updates were applied right before the decrease in backup speeds?

I doubt the links in the canned Veritas response will be of much help, really, as you have probably already seen them and gone through it...but is there any way, since this is a dedicated backup server, that you can recreate it as it was before those updates? If your backup speeds increase, then apply them again and see if they decrease again immediately.

Discussing speed issues with Veritas is typically a run-around game of checking other people's hardware and their settings...