I agree that synthetic backups are good, but only if you run file backups.
If the system has an oracle, the synthetic backups are useless.
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu [mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Mark Phillips
Sent: Thursday, April 12, 2012 3:56 AM
To: JCrowe AT marketforce.com DOT au; Simon Weaver
Cc: veritas-bu AT mailman.eng.auburn DOT edu; veritas-bu-bounces AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] Advice & Help - Linux Server 14TB
I agree. We use synthetic fulls quite a bit.
They work really well for large filesystems that have relatively small incremental backups.
If you’re going to tape you’ll need at least 2 free tape drives for the duration of the synthetic full backup, one for the last full backup and the other for the one you’re constructing.
Also it’s best if you’re able to send incremental backups to staging disk and they remain on the staging disk when the synthetic full is being constructed, it saves on tape loading and positioning time.
If the incremental backups are going to tape avoid multiplexing them, it’ll slow things down.
Also if you’re going to tape when doing the first conventional full backup don’t multiplex it – this will make doing the first synthetic full backup slow.
I would look at synthetics ... not quite as large as you, but I backup around 8TBs on one linux (RHEL 4) server over the weekend (every weekend) and it completes in well under 24 hours. (About 16-20 hours from memory)
The very first backup has to be a full, but once that is out of the way, you should be able to do a full synthetic every weekend in well under 48 hours (I'm going on what I have above so is just a guess - you may be much faster than my infrastructure as its nothing flash ... though it is completely gigabit)
I should add that I've been using synthetics on this particular server for around 4.5 years now, and they are reliable and fast - unless you have to "re-seed" the synthetic with an initial full backup; I have had a few go bad such that I have had to re-seed the backup, but that's been rare and only happened 2-3 times in all that time. HIGHLY recommended for large backups.
From: "Simon Weaver" <Simon.Weaver AT iscl DOT net>
To: <veritas-bu AT mailman.eng.auburn DOT edu>,
Date: 11/04/2012 09:16 PM
Subject: [Veritas-bu] Advice & Help - Linux Server 14TB
Sent by: veritas-bu-bounces AT mailman.eng.auburn DOT edu
I am hoping you can help....
Im not too familiar with Linux, but we have a RedHat Box, that is a VM Guest on an ESX Host, that has RDM's totalling 14TB
The backups are done over the LAN - Painfully slow as you can imagine.
Im wondering what options I have in terms of trying to improve performance for this client. So far its taking close to 3 days to run.
It is on a 1GB Network, as I understand. But does anyone have any suggestions?
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