[SunHELP] query on "tape" operation

[Peter Stokes]

Hi

It would be useful to know what tape drive you have (is it 2/4Gb drive?)

I am assuming it is 2/4Gb DDS1 tape drive. This has a nominal uncompressed
capacity of 2Gb and UPTO 4Gb with hardware compression on the tape. So if
your data will compress well, you will get 4Gb of data (this will include
the header stuff etc). If it does not compress well, you will get less. Also
the blocking size for the data can have significant effect on the amount of
data. General rule is smaller blocking size = less data on the tape as it
wastes more tape to store small blocks of data, than large blocks.

Hope this helps

Peter
---------------------------------
Peter Stokes
Ashlyn Computer Services Ltd
Tel: +44 (0)1636-627900
Fax: +44 (0)1636-627909
Mbl: +44 (0)7977-532320
Web: http://www.ashlyn.co.uk
---------------------------------

-----Original Message-----
From: sunhelp-admin at sunhelp.org [mailto:sunhelp-admin at sunhelp.org]On
Behalf Of TAG DBA
Sent: 14 December 2001 11:17
To: 'sunhelp at sunhelp.org'
Subject: [SunHELP] query on "tape" operation


Solaris 8 on Sun E450
----------------------------------
I was trying to estimate how many sets of database backups can fit onto one
4 GB DAT tape.
One set approx is of size 1 GB. So atleast 3 sets should get copied to tape.
The command I type is :
$ tar cvf /dev/rmt/0cn $DUMPS

However during the third copy operation I got this error:

a ./archlogs_14_dec_01.Z 696322 tape blocks
tar: write error: unexpected EOF
Backing up export dump expTAG1SPZ_Fri_full.dmp.Z and log file
/s0003/TAG1SPZ/expdumps/expbu_TAG1SPZ_14_dec_01.log ....
a expTAG1SPZ_Fri_full.dmp.Z 563396 tape blocks
tar: write error: unexpected EOF
Ending Backup Fri Dec 14 16:54:19 GMT 2001

Does it mean that the tape is full ???
Regards,
~aslam
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