Transfer rate on ultrium tape drives

[David_711]

Hi,
Somebody know how i can check the tranfer rate when i am doing a backup to a any tape drive ultrium on my hpux 11.11.? 1,5 mpbs, 2mbps..etc
This is posible?

I know the utility for tapes ultriums (ltt), but with this utility i can't check the rate when i am doing a backup only wiht test.
Please help,
Thansk

[Steven E. Protter]

Shalom David,

The tranfer rate should be checked with a real world backup of real world files.

Pick a filesystem on local disk and back it all up with fabackup.

Then do the same thing on a SAN LUN.

Divide the bytes backed up by the duration of the backup which fbackup keeps track of.

Then you have a real world transfer rate. The only tool you need is a calculator.

SEP

[Ivan Ferreira]

If the ultrium is connected to a SAN, you can use the portperfshow command in the switch to display the transfer rate.

[Peter Nikitka]

Hi,

just checked some data in a log of one of our backups to LTO:
We got 10.2 MB/s but compressing of other data was running in parallel, so I cannot say if that was maximum speed.

Testing in your enviroment may give other values, of course.

mfG Peter

[A. Clay Stephenson]

One of the easiest methods is to use Glance -> Processes (select your backup process) -> Open Files and note the rate at which the file offset is changing for the tape device node. One of the biggest limiting factors is not the speed of the backup device itself but rather how fast the input files can be read. Singly-threaded applications like tar and cpio have a difficult time feeding a fast tape drive. Use fbackup or better still a commercial product like Data Protector to combine the output of several disk reading agents into the input stream for the tape drive.