[CentOS] Recommendations for a "real RAID" 1 card on Centos box

[Ross S. W. Walker]

nate wrote:
> 
> Therese Trudeau wrote:
> 
> > Ah great i'll check out the URL thanks.
> >
> >  One thing, an earlier poster reccomended RAID 5 instead of RAID 1.
> > I guess if one only has 2 drives RAID 1 is the way to go but if I have 4
> > drives he said go with
> > RAID 5 over RAID 1.  Isn't RAID 1 mirroring a better solution for a 4 drive
> > array or am I missing something here?
> 
> Depends on your needs, RAID 1 is certainly faster. RAID 1+0 faster
> still, but requires more disk(s/space).
> 
> Going back to my preferred array vendor, 3PAR, their software/hardware
> provides the ability to do online RAID conversions to/from RAID 0, 1+0,
> and 5+0 (3+1 parity to 8+1 parity) with no impact to the server. It
> also provides the ability to run multiple raid levels on the same
> physical disks because the RAID is made up of portions of the disks
> (each disk split into 256MB chunks), rather than the full physical disks
> themselves. Really flexible/powerful/fast. I love it! On my array I
> run RAID 1+0 on the outer regions of the disk(~7% faster than
> the inner regions), and RAID 5+0 (8+1) on the inner regions of the
> disks.
> 
> Of course this sort of technology isn't priced for the desktop unless
> your doing something like desktop consolidation with virtualization or
> remote application hosting/thin client.

I just had to put my .02 in here:

The key requirement here is technology for the desktop.

Since this is going to be a single user box I really do not recommend
mucking around with hardware RAID at all.

You have 4 disks, create a software RAID mirror out of disk 1 and 2,
and a software mirror out of 3 and 4.

Make a VG out of the first mirror, call it "CentOS" and put the OS and
all your applications there, including "home".

Make a VG out of the second mirror, call it "Work" and put all your
work material there.

Then you can always upgrade the OS disks without touching your work
disks.

You can export your work disks VG, move the disks over to a new
machine and work there.

Create snapshots of your work disks, backup your work onto your
OS disks, etc.

A couple of 80 or 160GB disks for the CentOS VG, a couple of 320GB
disks for the Work VG and your good to go.

If you want any advise on setting up LVM and LVs for different
file systems I, and everyone on the list, would be happy to
give their opinions.

This is the easiest, most flexible and fastest way to get a
good performing redundant desktop setup.

-Ross

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