Backup using dltvs80 slower than old seagate dat drive

[CA1129714]

Ive just purchased and installed a Storageworks DLT VS80 external drive. It is connected to the on-board scsi (lsi ultra320) on a dell poweredge2600, windows 2000 sp4, BackupExec 9.0.

Running the HP StorageWorks Library and Tape Tools dignostics, throughput rates are 300mb/min at 2:1 compression and 180mb/min at 3:1 compression. When performing a backup from Backup Exec, the maximum throughput rate that can be achieved is 182mb/min, which is slower than my older Seagate DAT drive(usual rate was 240mb/min) which was connected in the same way.

Is this speed normal for this particular setup, or should I be able to backup at the 300mb/min rate that the diagnostics achieve?

[Lewis Finch]

Dave,

In your back up exec software change your block size to 64k and see if this helps

[CA1129714]

The block size has already been set to 64k, along with the other settings as recommended in the HP document titled 'DLTVS80 Performance (Capacity and Speed)'

[CA956809]

I am experiencing the same problem on a recently installed HP Storageworks Autoloader DLTVS80 1/8. The drive starts and stops continuously while backing up. I contacted Veritas for help and all they did was point me to the manual where it recommends playing with the buffer and block size settings. Surely someone has experienced this problem before and can help with the throughput issue.

[CA1130306]

I am also having the same exact problem with the same drive.

I'm sure we're not the only ones with this problem - anyone have any new ideas?

[meloni]

Several factors may cause poor performances:

I would recommend to run the L&TTtest called " device performance". This test will generate data in the server memory and send it to the tape. You can then check the whole path: memory server, pci bus,hba, scsi cable, terminator, vs80.

The second test is called "system Performances" and will check how many time it took to read data from HDD, and will give you the performance result (there is also a write to disk performance test if needed)

Now you have to identify wich of the two test do not let you reach the 6 MB/sec.

If it is the first one, then check for any running SW in the server memory, check for unique IRQ assigned to the PCI HBA, check for new HBA drivers or try older one (some time this is the solution), install last tape drivers from vendor (HP) or replace them with ISV one (Veritas), replace cables and terminators, use new brand cartridges, and diagnose the vs80 with r/w test, media validation test, and isuue a L&TT Sticket

Hope these steps will sort some results

Marino

[BR19682]

Hi there.
A good chance is to check. whether you have set the software compress on.
If this comes togehther with hardware compression, it will bring your performance down to half of the normal.
Rgds
Alexander M. Ermes