topic Re: write on a DDS4 tape (compressed) in Operating System - HP-UX

write on a DDS4 tape (compressed)

Nabil Boussetta — Thu, 01 Sep 2005 09:52:04 GMT

i'd like to to backup my database(size 35 GB) on a DDS4 tape. how to write on compressed mode ?

Re: write on a DDS4 tape (compressed)

RAC_1 — Thu, 01 Sep 2005 09:55:26 GMT

Use the device file that supports compression. Depending upon data, you may/may not want to use it.

lssf /dev/rmt/0m

Run lssf on every device files and use the one that says best density. Also during such operation, you should see compresson LED blinking on the dds drive.

Re: write on a DDS4 tape (compressed)

Raj D. — Thu, 01 Sep 2005 10:11:48 GMT

Hi Nabil ,

Check the "at&t best density available" ,(ex: /dev/rmt/0m ) with lssf , and try taking a backup , hope it will go upto 36GB to 40GB, being dds4 drive.

Cheers ,
Raj,

Re: write on a DDS4 tape (compressed)

Alessandro Pilati — Thu, 01 Sep 2005 10:19:52 GMT

Check this:
ls -la /dev/rmt

check these suffixes:
l - low density
m - medium density
h - high density
u - ultra density
c - compression enabled
n - no rewind
b - Berkly standrard

Usually if you use BEST, it does in any case hardware compression ( if I'm not wrong )...

check for the "c" suffix for the compression enablement.

Hope you can get extra helps...

Regards,
Alex

Re: write on a DDS4 tape (compressed)

Nabil Boussetta — Thu, 01 Sep 2005 10:28:43 GMT

i have the following device files under /dev/rmt:

# ls
0m c1t2d0BEST c1t2d0DDS
0mb c1t2d0BESTb c1t2d0DDSb
0mn c1t2d0BESTn c1t2d0DDSn
0mnb c1t2d0BESTnb c1t2d0DDSnb

which device file should i use ?

Re: write on a DDS4 tape (compressed)

RAC_1 — Thu, 01 Sep 2005 10:34:35 GMT

c1t2d0BEST

You can use any one that says best density when you do "lssf *"

Basically they are same files. Check it with
ll -il. check inodes.

Re: write on a DDS4 tape (compressed)

Nabil Boussetta — Thu, 01 Sep 2005 10:38:17 GMT

ok, il will try to test that