Multiple Drives in Tape Library Unit

[DaTaSPiKe]

Hopefully this won't be a problem, but I posted this in the ARCserve section as well...

http://www.tek-tips.com/viewthread.cfm?qid=1026909&page=1

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System Stats:
Dell PowerVault 750
ARCserve v11
Spectra-Logic 15 Tape Library w/2 Sony AIT-3 Drives

Issue:
Currently I am on a modified GFS schedule. M - F Differential backups (100 to 260 GB) and Saturday a Full Backup of almost 700GB. We recently placed a second AIT-3 Sony drive in the library and spoke with our CA rep and he recommended a Tape Library Option in order to utilize BOTH drives in backing data up. We went with his recommendation, and now have the TLO, but I am still only using ONE drive during my backups, and my Differentials are taking 12 hours, while my Full is taking close to 30 hours. I called the rep, and he suggested Multiplexing. Tried that, but that only opened up several threads to backup more machines at once, and not utilize BOTH drives.

What am I doing wrong?
What needs to be done to use BOTH drives, in the same Library?
Can this even be done?

Any help would be appreciated.

Thanks,
Chris

 

[davidmichel]

First off it is my understanding that for libraries with more than one tape drive TLO is needed.

Two ways:
1) setup two Groups
2) multi streaming

1) With libraries Groups are setup per slots. So for example a library with 50 slots can be setup into two Groups of 25 slots each. The one backup can be submitted to Group0 and one backup can be submitted to Group1.

2) With the Enterprise option multi streaming can be used. Multi streaming takes one big job with small subjobs and each subjob goes to a different drive. It will use all the drives that are available at the time the job starts.

Multiplexing is good if the flow of data can not keep up with the throughput of the drives.