[TriLUG] Department server sonfig suggestions please.

[David A. Cafaro]

On Tue, 2004-08-03 at 16:19, bp wrote:
<snip>
> 
> Below is my current quick burn-in config and I have a couple questions 
> from it already:
> 
> 1) Any advantage to the RAID0 swap partition over two disks?  RAID0 
> performance boost make up for the S/W overhead of RAID0?

Maybe some advantage if you are swapping a lot.  But if you are swapping
out a lot, I'd probably start looking at other solutions and reasons why
you have massive swapping (could be lack of funds for the proper amount
of RAM for the machine, but again, things going to swap shouldn't be
going in and out often)

> 
> 2) How does linux software RAID5 work for dissimilarly size SOFTWARE RAID 
> slices? See sdb vs. the rest of / members.

Last I checked it doesn't, each member partition of a RAID5 system needs
to be the same size.  So you would have to loose 1.5GB on each disk
after sdb based on your layout.

> 
> 3) Should the OS really run under RAID5?  I can afford a little downtime 
> to reinstall an OS; and restore config backups.  I'm just looking for some 
> redundancy on home directories and /staging.

In my world it's always nice to run the OS on RAID5 if you have the
option.  Remember that it's not just the down time to reinstall the OS. 
On RAID5 the system isn't going to stop running when a disk fails (it
will slow down).  You can even put the /boot on the raid, and with some
carefull grub in MBR setup you can even make sure that your system
always reboots even with a failed disk.  Of course this is all about
making the system hard to knock down.

> 
> 
> Current setup for burn-in:
> 
> 
> How would you guys slice up this box to fill our need?

If you really wanted to have your swap on raid0, you might as well
stripe it across all the disks the same way as the raid5.  

If it were me, with this system.  I would create something like this:

[sda]
50mb  md0-raid5 /boot
4gb   md1-raid5 /
31gb  md2-raid5 /files (/files/staging etc..) 
950mb md3-raid0 swap
[sdb]
50mb  md0-raid5 /boot
4gb   md1-raid5 /
31gb  md2-raid5 /files (/files/staging 
950mb md3-raid0 swap
[sdc]
50mb  md0-raid5 /boot
4gb   md1-raid5 /
31gb  md2-raid5 /files (/files/staging 
950mb md3-raid0 swap
[sdd]
50mb  md0-raid5 /boot
4gb   md1-raid5 /
31gb  md2-raid5 /files (/files/staging 
950mb md3-raid0 swap
[sde]
50mb  md0-raid5 /boot
4gb   md1-raid5 /
31gb  md2-raid5 /files (/files/staging 
950mb md3-raid0 swap
[sdf]
50mb  md0-raid5 /boot
4gb   md1-raid5 /
31gb  md2-raid5 /files (/files/staging 
950mb md3-raid0 swap

Truthfully, I'd probably think it out even more, but this is just a
quick idea of what I might do.

-- 
David A. Cafaro
dac(at)cafaro.net
Admin to User: "You did what!?!?!"