DLT7000 Specs?

[mikeyt1513]

I have a Timberwolf 9730 with 2 DLT7000 drives, running Legato Networker 6.0.3 on Sun Solaris 2.6.
We recently upgraded from Networker 5.5 and now our backups are taking twice as long.
The tape drive is backing up at roughly 800k/sec. What are the specs for how fast a dlt7000 drive should go. Would you know if they are using different compression on the new rev of legato which takes longer, the tapes are holding roughly 50% more than they were before. Used to do around 40GB per tape, they are now up around 65GB per tape.

I would greatly appreciate a pointer in the right direction to solve this issue.

Sincerely,

Michael T

 

[UlteraTapeRAID]

The DLT7000 tape drives' native transfer rate is 5MB/Sec. I would first suspect the block size being used by Legato. Check the NSR device resource attributes using nsradmin. Make sure the volume block size is set to 64K or larger.

Also, since the tapes are storing more data than before, it sounds like compression is enabled. Look at the drive LED's that show the media format and compression mode. Verify the compression LED ON during the backup.

If the backup data stream is not fast enough to keep the tape drive streaming, excessive tape start/stop or shoe-shining can happen that causes the overall performance to degrade. To see if this is the case, try running a backup with compression OFF to see if the backup streams data better with a higher overall backup speed.

 

[UlteraTapeRAID]

The DLT7000 tape drives' native transfer rate is 5MB/Sec. I would first suspect the block size being used by Legato. Check the NSR device resource attributes using nsradmin. Make sure the volume block size is set to 64K or larger.

Also, since the tapes are storing more data than before, it sounds like compression is enabled. Look at the drive LED's that show the media format and compression mode. Verify the compression LED is ON during the backup.

If the backup data stream is not fast enough to keep the tape drive streaming, excessive tape start/stop or shoe-shining can happen that causes the overall performance to degrade. To see if this is the case, try running a backup with compression OFF to see if the backup streams data better with a higher overall backup speed.

 

[Schotte]

If disabling compression improves performance, the bottlneck is not the drives......its something else. This is a general missunderstanding in the industry as a whole.....

 

[Schotte]

Do you need any further help?