DAT "AUTO"

[Nobody's Hero]

First I'd like to thank everyone for providing help to get this auto loader working.
1) had to load schgr (AC HARDWARE DRIVER) into kernel

2) had to load sctl (SCSI PASS THROUGH) into driver.

3) had to write a script to use in a config file for fbackup to use when at volume change time.

My question. I am tring to purposly fill up tapes as fast as possible to test this volume change. Running fbackup is using data compression that allows more than 24gig on a dds3 tape. How do I tell fbackup to not use compression?

[BFA6]

Hi,

I think SAM will allow you to create custom device files for tape drives.
It might be possible to create a device file without compression.

Hilary

[Jeff Schussele]

Hi Robert,

It's not fbackup that's compressing - it's the device itself. Check your /dev/rmt/... entries, if they all have BEST in them then you'll have to create a new device w/o BEST.
See the following link for instructions

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90698/B2355-90698_top.html&con=/hpux/onlinedocs/B2355-90698/00/00/51-con.html&toc=/hpux/onlinedocs/B2355-90698/00/00/51-toc.html&searchterms=tape%7cdevices&queryid=20020516-062359

Basically you'll be using the mksf comamnd to create the device - then you'll just use it instead.

HTH,
Jeff

[melvyn burnard]

This has nothing to do with fbackup. It is the device itself doing hw compression.
Also check out the device file you are using, if you do lssf /dev/rmt/0m for example you wil see something like:
stape card instance 6 SCSI target 0 SCSI LUN 0 at&t best density available at address 10/12/5.0.0 /dev/rmt/0m

Note the "best density available"

you may try to make a new device file and set it for NO COMPRESSION using SAM

[Helen French · Accepted solution]

Hi Robert:

You need to create a device file with 'mksf'. The device file 0m corresponds to the device file *c2t0d0BEST*. These device files will automatically switch on the data compression in the tape drive, provided that the tape drive supports compression. If you want to write to a tape without compression, then you need to create one device file with mksf command:

# cd /dev/rmt
# mksf -C tape -b DDS3 -H hard_path /dev/rmt/0m_nocomp

HTH,
Shiju

[Nobody's Hero]

Shiju,
where in this command does it state 'no compression'?

mksf -C tape -b DDS3 -H hard_path/dev/rmt/0m_nocomp

[Helen French]

Hi Robert:

By default, this command will create without compression. If you need compression, then you need to use -c option with the mksf command.

Also use the -n option for non-rewind. Read man mksf for details.

HTH,
Shiju

[Nobody's Hero]

di I need to say '-b DDS2 or 1.' Is this what is controlling the compression?

Anyone?

[Nobody's Hero]

Thanks Shiju!! I'll give it a try

[Helen French]

Hi Robert:

Again, The -b option is for specifying the tape density or Bits/inch. This is specific to the tape drive you are using (DDS1, DDS2, DDS3 etc). This does not have any impact with compression. All these drives support compression and normal methods

HTH,
Shiju

[Jeff Schussele]

Hi Robert,

No, that's what define the BPI (bits per inch) or density.
The following are available:

-b bpi Bits per inch or tape density. The recognized values for bpi are: BEST, D1600, D3480, D3480C, D3590, D3590C, D6250, D6250C, D800, D8MM_8200, D8MM_8200C, D8MM_8500, D8MM_8500C, DDS1, DDS1C, DDS2, DDS2C, NOMOD, QIC_1000, QIC_11, QIC_120, QIC_1350, QIC_150, QIC_2100, QIC_24, QIC_2GB, QIC_525, QIC_5GB, DLT_42500_24, DLT_42500_56, DLT_62500_64, DLT_81633_64, DLT_62500_64C, DLT_81633_64C, or a decimal number density code.

Depends on what model the drive is.

Rgds,
Jeff

[Nobody's Hero]

Thanks everyone, especially Shiju.

BINGO.....I'm happy.