RE: Save to Disk/Tape

[Jeff Bull <Jeff.Bull@xxxxxxxxxxxxxxx>]

One of the problems you will inevitably be suffering is related to the
disk-arm utilisation.  A save to *savf will be generating approx double of
that to tape; if your *savf is in the same ASP as the data being saved, that
means your disk arms are working twice as hard.  The options in this
instance are therefore : (a) add more disk arms to spread the load (b)
create a user-ASP with sufficient capacity to contain the *savf backup.
This isn't the sole solution because the user ASP disks may need to be on a
second IOP, also there may be an adverse impact on performance in the system
ASP if you take the user-ASP disks from there.

Personally, I would buy some relatively cheap, second-user 4 or 8GB disks
with another IOP, create a user ASP with them.

Though taking a detached view on your backup processing ... why are you
backing up to tape AND *savf?  Unless this is a restricted-state backup
(e.g. *Nonsys), could they perhaps run concurrently for some of their
processing period - start the backup to *savf 15 to 20 minutes after the
backup to tape?

Kind regards,

Jeffrey E. Bull
OS400 Software Support Consultant

IBM Certifiied iSeries System Implementation Expert
IBM Certified AS/400 System Administrator 

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ITM Group Ltd, Latimer Square, White Lion Road, Amersham, Buckinghamshire,
HP7 9JQ, United Kingdom


-----Original Message-----
From: Andy Youens [mailto:Andy@xxxxxxxxxxxxxxxx]
Sent: 07 July 2003 07:54
To: midrange-l@xxxxxxxxxxxx
Subject: Save to Disk/Tape


Morning All

I have a client who is doing 2 nightly saves, one to save file, the
other to tape (magstar MP 3570 Tape subsystem).

The disk save takes 2 hours, where the tape save takes 1:40.

Anyone any ideas on how we can get the disk save quicker?  Disk
utilisation is low, with the data spread even across the disks.

Client is running V4.3

Many thanks

Andy Youens
FormaServe Systems Ltd
91 Redland Drive
Loughton
Milton Keynes  MK5 8FL
T: +44 (0)1908 609500
W:www.formaserve.co.uk <http://www.formaserve.co.uk/> 
E: Info@xxxxxxxxxxxxxxxx <mailto:Info@xxxxxxxxxxxxxxxx> 

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