[CentOS] Multiple RAID support in CentOS?

Brian Mathis brian.mathis at gmail.com
Sat Jan 30 02:16:45 UTC 2010


On Fri, Jan 29, 2010 at 9:09 PM, Ian Blackwell <ian at ikel.id.au> wrote:
> On 30/01/2010 12:09 PM, Victor Padro wrote:
>> Hello,
>>
>> I was wondering if someone could help me,
> I'll try...
>> I want to use one array with the 2 500GB HDDs in RAID1 for the OS and
>> for some VMs,
> That will work OK.
>> and the other 4 1TB HDDs I want to create an array in
>> RAID5 or RAID10 for file sharing across my home Network.
>>
> You can use these disks in a RAID5 array, but not RAID10.  I fairly sure
> you need more than 4.  RAID10 is mirrored, so you only have "2" disks in
> the array, which isn't enough for parity/striping stuff.  You need at
> least "3", which would mean 6 disks for RAID10.
>
> Having said that, I'm assuming you want to use the entire hard disk as a
> participant in an array.  You could create 2 x 500Gb partions on each
> disk and then you have 8 x 500Gb partitions to use in a RAID10 array.
> This approach sacrifices some redundancy though.  If a disk dies
> entirely, then you will lose two participants in the RAID array, which
> may or may not be catastrophic - it depends on what you put where...
>> I found a guide but it's a little bit outdated and it's for Debian...
>>
>> Do you have any other pointer I can read/use?
>>
> http://wiki.centos.org/HowTos/SoftwareRAIDonCentOS5
>
> I've mostly installed RAID arrays at install time, which you'll need to
> do as well if you want to put the OS on a RAID1 array.
>>
>> TIA.
>>
> Ian

RAID10 does not use parity, it's just a mirror of stripes, so 4 disks
will work perfectly fine with it.

Use RAID10 for speed, and RAID5 if the space is more of an issue.
With RAID10 you lose 1/2 the total space, and with RAID5 you lose 1
disk's worth.


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