How to view and change the default block size of tape device?

[MA Qiang]

Tape device is /dev/rmt/0m in HP-UX 11.11.

Thanks.

[A. Clay Stephenson]

Tape device nodes in HP-UX are rather unique in that identical major/minor device number tuples on different machines can have very different characteristics because there are more variables than will fit in the available bits. Part of the minor device number is used an an index into an array that actually describes the device. Note that even with this, for many tape drives the blocksize is variable and is controlled by the application rather than the device driver. In any event, the key to what you are trying to do is the insf command (which manipulates the in-memory array). Man insf and scsi_tape and that should get you pointed in the right direction.

[Trupti]

Hi,
Are you using data protector for taking backups of servers.
If yes ,then start DP GUI.Go to Devices & media.yhen click on drives.Go to properties,then go to settings.Click on Advanced option,there you will get sizes option.There you can manage block size for drive.

Trupti M.

[MA Qiang]

Thank Trupti. I am not using DP. I want to know how to get/set the block size of the tape driver by CLI.

[Tor-Arne Nostdal]

Hi,
You want to know the block size used by CLI..

What do you mean? CLI = Command Line Interface ?

Clay's answer is very good.

The blocksize is set by the application you use for writing the tape.

Perhaps reading the manpages for the application might give you an answer.

/Tor-Arne

[A. Clay Stephenson]

AS close as you are going to get is the lssf command and also man 7 mt. It describes how the internal properties index is maintained.

[MA Qiang]

The output of 'lssf /dev/rmt/0m' is
stape card instance 2 SCSI target 3 SCSI LUN 0 at&t best density available at address 0/0/11/0/0.3.0 /dev/rmt/0m.

I can not get the block size of /dev/rmt/0m.