Veritas-bu

[Veritas-bu] Tape capacity

2002-03-11 07:08:15
Subject: [Veritas-bu] Tape capacity
From: SDaubigne AT bordeaux-bersol.sema.slb DOT com (DAUBIGNE Sebastien - BOR ( SDaubigne AT bordeaux-bersol.sema.slb DOT com ))
Date: Mon, 11 Mar 2002 12:08:15 -0000
Be aware that the 80 Gb capacity relies on a 2:1 compression ratio, which is
an average and is less than usual for database files.

The only significant capacity of a tape is the uncompressed capacity (40 Gb
for DLTIV). 
Hence you have to evaluate your data compression ratio to compute the
compressed capacity.

 For instance, ASCII files usually have 1:10 compression ratio, which leads
to a theorical capacity of 400 Gb for DLT IV.

Maybe you could use the following command to evaluate your data compressed
size and compute the compression ration (assuming "compress" and the DLT
driver's compression algorithms are equivalent) :

compress -cf < /dev/....../my_raw_volume  | wc -c

---
Sebastien DAUBIGNE 
sebastien.daubigne AT sema DOT fr <mailto:sebastien.daubigne AT sema DOT fr>  - 
(+33)
(0)5.57.26.56.36
Sema Global Services - AFM/DW/Pessac

        -----Message d'origine-----
        De:     Prabhala, Rama [SMTP:RPrabhala AT forestpharm DOT com]
        Date:   vendredi 8 mars 2002 22:12
        À:      veritas-bu AT mailman.eng.auburn DOT edu
        Objet:  [Veritas-bu] Tape capacity


        Hi there Gurus, 

        I am using a 40/80G DLT IV tape for backing up INformix database (
raw volumes ) of size - 210G. The whole backup comes on a sngle tape. How is
it ? Is it because of the Raw volumes ?

        Regards, 

        Rama 
        493-7058 
        

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