Amanda-Users

Re: amrecover very slow

2004-10-20 05:41:00
Subject: Re: amrecover very slow
From: Paul Bijnens <paul.bijnens AT xplanation DOT com>
To: Joe Konecny <jkonecn AT green-mfg DOT com>
Date: Wed, 20 Oct 2004 11:31:22 +0200
Joe Konecny wrote:

FreeBSD 5.2.1, Amanda 2.4.4p2

Had to do the first real amrecover today and it was
painfully slow.  I am using indexing and the file
to recover was about 140K.  It took from 14:47 to
16:22.  Any tips?  Here is a link to the debug file
if anyone wants to look at it... (It's about 500K)

http://www.green-mfg.com/amrecover.20041019144747.debug


Different possibilities.
First make sure the network is not in the way (e.g. a duplex
mismatch on one of the switches, frequent mistake).

Then, do you have "amrecover_do_fsf yes" in the configuration?
If not, then amanda will skip over the tape files by reading them.
If the image you need in near the end, that can take a while.

Next, how large is the image itself.  If the dump file is 30 Gbyte
then it still takes some time to crawl through that amount to locate
your 140K file.  A tape device is a sequential device.  Indexing
with amanda does not turn it into a random access device.

What is the raw speed of the tapedevice? Is it a DDS1 reading at 200Kbytes/sec, or is it some superfast device doing 12Mbyte/sec sustained? (Over a 100Mbit switch that's still limited to 6 Mbyte/sec,
maybe stops streaming on the tapedrive.)


--
Paul Bijnens, Xplanation                            Tel  +32 16 397.511
Technologielaan 21 bus 2, B-3001 Leuven, BELGIUM    Fax  +32 16 397.512
http://www.xplanation.com/          email:  Paul.Bijnens AT xplanation DOT com
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