On Sat, Jun 5, 2010 at 10:19 AM, Leslie Rhorer [off-list ref] wrote:

quoted

-----Original Message-----
From: linux-raid-owner@vger.kernel.org [mailto:linux-raid-
owner@vger.kernel.org] On Behalf Of Carlos Mennens
Sent: Wednesday, June 02, 2010 8:00 AM
To: Mdadm
Subject: Re: RAID Configuration For New Home Server

On Wed, Jun 2, 2010 at 3:54 AM,  [off-list ref] wrote:

quoted

There are about as many answers to this as there are people using your
setup so let's all agree that there's no "one way" of doing things.

Thanks for all the suggestions and you guys are right. There will no
right or wrong answer here but I just want to make sure I am not doing
anything that will hinder / limit performance in my system. At most my
system will simply idle and do nothing more than store a few files for
me so I think RAID5 is going to be my selection for my / file system.
I have 4 identical drives and need to partition them all the same to
avoid any inconsistencies across the RAID array. Since Grub doesn't
support RAID5 for /boot, I will need to make a 4 disk RAID1 for /boot
& do the same for Swap. Does this look reasonable to you guys?

Partitioning the 1st disk below:

/dev/sda1 100 MB - RAID (bootable)
/dev/sda2     2 GB - RAID
/dev/sda3 320 GB - RAID

Do that same partition schema above for all 4 drives and then create my
RAID:

/
mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sda3 /dev/sdb3
/dev/sdc3 /dev/sdd3

/boot
mdadm --create /dev/md1 --level=1 --raid-devices=4 /dev/sda1 /dev/sdb1
/dev/sdc1 /dev/sdd1

Swap
mdadm --create /dev/md2 --level=1 --raid-devices=4 /dev/sda2 /dev/sdb2
/dev/sdc2 /dev/sdd2

       It's certainly workable.  You might consider something other than
RAID1 for your swap partition.

Looks reasonable. Some comments:

1) I didn't bother using RAID on my /boot. I just installed grub on
each of the 3 drives but only boot from the first one. If that
partition goes bad I can boot from the second or third drive any time
by just telling BIOS to use a different drive. This saves me from
dealing with any mkinitrd stuff. I've never had a boot partition go
bad because of the drive itself in 14 years running Linux. They go bad
because I write the wrong stuff there. RAID doesn't solve that
problem. This method does require that I update the two backups by
hand once in awhile. That's OK by me.

2) I don't use RAID for swap. I let the kernel do that internally. I
almost never swap out on my home server so trying to protect that with
RAID for the few moments I might use it seems like overkill to me.

3) Your main RAID is exactly what I use on my home server, albeit I
use 3 drives, not 4.

HTH,
Mark
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