Amanda-Users

Re: enabling hardware compression ?

2004-08-23 23:48:58
Subject: Re: enabling hardware compression ?
From: Frederic Medery <dist-list AT LEXUM.UMontreal DOT CA>
To: brian AT wadsworth DOT org, Mailing List Amanda User <amanda-users AT amanda DOT org>
Date: Mon, 23 Aug 2004 15:12:52 -0400
Thanks,
in fact what I want is to speed up my backup so i moved my tape charger to the biggest server, now I have a /amanda with 160 GB of free space. I thought that HW compression would also speed up my backup.

thanks again

Frederic Medery
System Administrator

LexUM, University of Montreal



Brian Cuttler wrote:

Fred,

Fact
The options are not exclusive. You can SW compress on the client
or on the server or in the HW having nothing to do with the choice
of dump v tar.

Opinion
HW compression is great if you are trying to save CPU on the client
or server, but doesn't allow you to estimate tape usage as well since
amanda doesn't learn from the drive what the compression ratios are
for the file systems you are dumping.

er, I should say the DLE - disk list entries, since tar allows you
to put to tape (or disk file) things other than "partitions".

                                        YMMV

On Mon, Aug 23, 2004 at 02:52:29PM -0400, Frederic Medery wrote:
Hello, I'm using amanda with IBM 3581 tapechanger,
my tapetypes.conf is :

# IBM LTO Ultrium 3581 tape Charger
define tapetype IBM-LTO3581 {
       comment "IBM LTO Ultrium 3581 (Hardware Compression off)"
       length 100608 mbytes
       filemark 0 kbytes
       speed 13120 kps
}


I'm gonna use dump instead of tar so I want to enable hardware compression, but I can'y find any in the amanda doc ?

Some Hints ??

Thanks !!!!

--
Frederic Medery
System Administrator

LexUM, University of Montreal

---
  Brian R Cuttler                 brian.cuttler AT wadsworth DOT org
  Computer Systems Support        (v) 518 486-1697
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