topic Re: DLT VS80 performance in StoreEver Tape Storage

DLT VS80 performance

Steve Friday — Wed, 17 Apr 2002 10:13:10 GMT

We are backing up an NT4.0 server across the network to another NT4.0 server.

We are using Omniback 4.1

We have used the PAT test to check performance and the ratio was 1.67Mb Per Sec, that would be nice, in real terms we are only getting 800K

Result of the 'Real Test' for the drive J:
Time: 17min., 7sec. (1713.15MB Processed)
Transfer rate: 1.67Mb/Sec

Any ideas?

Scsi card is a symc8xx

Re: DLT VS80 performance

CA628575 — Wed, 17 Apr 2002 11:29:43 GMT

The PAT tool measures your systems ability to provide data to the tape drive, it is not meant to measure what exact backup speed you should expect.

As long as the value reported by PAT is higher than the specified maximum sustained transfer rate for the tape drive you are using, your system is not holding up the tape drive.

The reason this is important, is that any time the system is slower in providing the data than the tape drive can absorb them, the drive will fall out of 'streaming' operations, and that will severly impact your backup performance.

It appears that this is not the case with your system.

PAT only looks at your system and the disk system you are getting the data from, it does not look at your backup application, the SCSI bus that connects to your tape drive, or the tape drive itself.

There are many more factors that can affect performance, such as block size on the tape drive, if other devices are sharing the SCSI bus to the tape drive, the backup application you are using etc.

I don't have the specification for the VS80 handy to see what the expected transfer rate would be.

Re: DLT VS80 performance

Steve Friday — Wed, 17 Apr 2002 11:37:03 GMT

We have just applied a firmware upgrade and the figures are now

1.72 gig across a network pre firmware upgrade 1hr 40mins

1.72 gig across a network post firmware upgrade 13Mins!!!!

Amazing

Steve

Re: DLT VS80 performance

CA756694 — Wed, 24 Apr 2002 13:47:10 GMT

Hey ...

Which version of firmware did you upgrade to, was it v50 ?

Has anything else changed on your system ??

We're always interested in good news although it's better if we understand exactly why 8-)

cheers

John

Re: DLT VS80 performance

Steve Friday — Thu, 25 Apr 2002 10:26:00 GMT

Firmware version applied was V050/OEM2. No other changes were made to the system.

Regards

Steve