Networker

Re: [Networker] How do I minimize recovery time?

2003-06-18 11:54:05
Subject: Re: [Networker] How do I minimize recovery time?
From: Jody Gregersen <Jody.Gregersen AT VISHAY DOT COM>
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Date: Wed, 18 Jun 2003 11:53:57 -0400
Well, actually I'm talking specifically about one server's SAP on Oracle
data.  The other servers are only 125, 87 and 34 GB apiece and are a bit
less important for continuity.  So the total amount of clients/pools would
be 4 but only the 500GB and 87GB would be needed quickly in a true disaster.

We have Gb ethernet at both locations so lan is not a big factor.  The files
range in size from 512MB to 4GB and there are 245 of them.  There are also
redo logs that are 100MB each and the amount of files depends upon the
amount of activity that occurred since the last backup (approx 190 files).

You've given me a great starting point for working this out.  I imagine
there has to be a way to set the target sessions on a drive via command
line.  You wouldn't happen to be able to point me in the right direction for
figuring it out would you?

Thanks so much,

Jody

Jody Gregersen
Infrastructure Engineer
Vishay Intertechnologies, Inc.

-----Original Message-----
From: Legato NetWorker discussion [mailto:NETWORKER AT LISTMAIL.TEMPLE DOT 
EDU]On
Behalf Of Neild, Jim
Sent: Wed, June 18, 2003 9:57 AM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: Re: [Networker] How do I minimize recovery time?

I had a similar dilemma that I had to work through.  Are you talking
about a complete environmental DR restore or a single/group (of)
server(s) (I assume the whole shi-bang)?

The higher your sessions and paralellism, the quicker your backup, the
slower your restore.  There is no "optimum" paralellism or sessions
settings as the variables can be huge (LAN speeds, file sizes, number of
files), so you must play and find your optimum.

What I have done is thoroughly optimize our backups and restores through
a lot of testing.  As a result, key servers backup at a paralellism of #
of savesets times the number of drives (sessions set to 1) allocated to
the pool.  For lower priority servers, I increase paralellism and
sessions so that backup and restore times are both acceptable to meet
SLAs.

How many clients, pools

-----Original Message-----
From: Jody Gregersen [mailto:Jody.Gregersen AT VISHAY DOT COM]
Sent: Tuesday, June 17, 2003 4:58 PM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: [Networker] How do I minimize recovery time?


Hi,

I'm running Legato 6.1 using Tru64 5.1a on an ES40 attached to an
ESL9326 jukebox with 8 TL891 drives.  We are setting up for a DR test
and I would like to have the shortest recovery time possible.  We run
separate backups rather than cloning.  We can get about 500 GB backed up
in about 5.5 hours using a parallelism of 32 and 8 target sessions per
drive (8 streams running to 4 tapes simultaneously).  To restore this
setup takes about 24 hours.  If I run with a parallelism of 16, the
backup takes about 8.5 hours.  We haven't tried a restore from those
tapes.  Does anyone know of an "optimum" parallelism for restoring or
some equation that could be used to determine what a restore time might
be?

Thanks,

Jody

Jody Gregersen
Infrastructure Engineer
Vishay Intertechnologies, Inc.

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