Slow performance Quantum DLT VS160

[John.Welch]

I have just replaced my OnStream ADR2 240sr tape drive with the Quantum DLT VS160. The 240sr backed up at about 300mb/min. The Quantum DLT VS160 backs up at about 116mb/min - on a new tape - while doing a transfer. The Quantum DLT VS160 is rated at 16mb/sec (960mb/min). Why is it not at least as fast as the 240sr? I got this drive because I wanted faster performance. The new drive continually starts and stops. The OnStream drive ran steady and only stopped between drives.

 

 

 

btw, If I run this same transfer from its current location to another hard drive instead of the tape drive, the transfer rate is about 1400mb/min. So I know the hard drive and Retrospect settings are okay.

 

 

 

Configuration:

 

• Retrospect 7 Single Server -- 7.0.5.102 and most current rdu.

 

 

 

I am running WinXP SP2, Intel 3.2Ghz HT processor, 1GB DDR PC3200, and using an Adaptec 29160 (Ultra SCSI 160 LVD).

 

 

 

This tape drive is the only thing on the chain and the only SCSI device currently installed.

 

 

 

The Quantum DLT VS160 firmware is the latest: major revision 37

 

 

 

I have disabled the Quantum DLT VS160 in the device manager.

 

 

 

The Adaptec adapter shows a transfer rate capability of 160.

 

 

 

I am not using encryption.

 

 

 

Hardware compression is set to "On" in the backup set. Although hardware compression does not show up in the device properties. Why is that?

 

[Lennart_T]

"Native capacity of 80GB at 8MB/second transfer rate

2:1 compression allows for 160GB capacity at 16MB/second transfer rate"

 

Even so, 8MB/s is 480MB/min.

 

What kind of tapes are you using? If you use old 15/30GB tapes, you get about 100MB/minute.

 

Have you tried the ASPI package?

http://www.adaptec.com/worldwide/support/drivers_by_product.jsp?cat=/Product/ASPI-4.70&sess=no&prodkey=ASPI-4.70

 

Apart from that, I have no clue.

[John.Welch]

Thanks. Using 80/160 VS1 tapes. I have tried ASPI. This is not a Retrospect issue. I have a trouble ticket going with Quantum now.

[igavin]

I have a hp/Quantum VS160 and had the same problem. The problem was caused by using the Microsoft driver for my Adaptec 29160 SCSI Card. Once I used the Adaptec driver, the tape performance increased dramatically (to 400-500 M/s). If the information cannot be written to the tape drive fast enough by your SCSI, Hard disk subsystem, etc., the drive has to stop, rewind a bit and start again to build up speed and stream.

 

Hope this helps.

Ian Gavin.