Installing Linux /Storage area network

[Rick Stevens]

On Mon, 2005-11-21 at 13:24 -0500, Nair, Murlidharan T wrote:
> I am trying to setup my server from scratch. I have to install the OS
> and set up SAN as database store. I also need to configure it. I have 4
> drives so I am thinking of configuring it as 4 drive -RAID 5 without the
> hot-spare. I have never done this before. Do you have any step by step
> procedure on how to do this? Thanks ../Murli

So you wish to install the OS on the normal IDE or SCSI (or SATA) drives
in the machine and reserve the SAN for database?  Ok, that's fine.

As far as the SAN is concerned, I always try to configure things with a
hot spare if at all possible.  If you need the space, then a 4-drive
RAID5 is fine.  If you can add a hot spare later, then that's even
better.

Each LUN on the SAN will appear as a SCSI disk (/dev/sda, /dev/sdb,
depending on what other stuff you have).  Configure your database to
use raw devices or set up partitions on those disks as you see fit.

Note, however, that multi-LUN setups will have problems as the default
kernels from Red Hat only look at the first LUN.  Just why they do that
is beyond me for an "enterprise" kernel (probing multiple LUNs is pretty
innocuous), but that's what they do.  To get around that, you need to
rebuild the kernel with "CONFIG_SCSI_MULTI_LUN=y" set and boot that
kernel.

If you can give us details on the system configuration (the number and
sizes of IDE, SCSI or SATA drives, SAN host adapter, SAN itself, etc.),
we will be able to advise you more completely.  Remember, these are just
_suggestions_...we aren't Red Hat employees here.

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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
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-     If you can't beat your computer at chess...try kickboxing!     -
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