Backup Central

Hello everyone,

I am currently backing up over 1.2 TB of media using BRU PE 2.2.0 and HP Ultrium 5 3000 SAS external drives. I am using the tape doubler mode within BRU to create a master and duplicate copy of the media. The problems I am encountering is that the tape drives are NOT backing up everything at the same speed. One seems to be going faster than the other. The other issue is when BRU asks me to insert the next tape to continue the backup, the tapes are not identical in size. One will stop at 757 GB and the other is 690 GB.

Has anyone come across this issue before? If so, please let me know what you think, or if you know how to fix the problems. I'm not sure if the problem is with BRU, or if the tape drives are not setup the same within HP_LTT. Maybe it could be the fact that I'm still running Leopard and not Snow Leopard? Please help!

If you're using HP 3000 external drives, those are LTO-5 drives and the if being used with LTO-4 tapes then the maximum capacity that you will get is 800GB. Anything higher needs to be considered a bonus.

Additionally, if you're backing up media files (which BRU PE is designed to do), you won't get much compression if at all.

The speeds of the drives will vary since you're backing up the exact same data to two different drives. Are you aware that it's not one read process to two write processes?

As for HP_LTT, that tool is primarily designed to update the firmware of the drives. Have you made sure that the drives are using the latest firmware? If each drive is using a different version then it could be changes in the firmware that's causing both the speed and size differences.

I can't say that I've ever heard of there being problems in different backup sizes when using two different drives at the same time, but the speed differences do make sense when you understand how tape is different than disk.

Did the BRU PE support provide you with any suggestions (that is...if you have support)?

Thanks for the info, Hummdis.

I just got further information from BRU and what they told me is that the doubler mode was designed not to make each backup identical in file sizes and that in the end of the backup, everything will eventually be backed up safely. My concern was based off of the fact that it was a multi-tape backup and thought there was an issue when the first tapes had different files sizes, but according to BRU, that is how things should be.

They also responded about the speed and that the decks won't operate simultaneously at the same speed. All my questions were answered and really had nothing to worry about. Main concern is that when I calculate the backups should be two tapes (two for master and two for duplicate), that one will be two tapes and the other three. Which in my line of work, doesn't help me accurately predict tape estimates. But I will be pretty close!