[CentOS] Multiple RAID support in CentOS?

Victor Padro vpadro at gmail.com
Sat Jan 30 03:12:20 UTC 2010


On Fri, Jan 29, 2010 at 8:09 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 I found a guide but it's a little bit outdated and it's for Debian...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
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Thank you Ian, but I disagree in your concept of RAID10:

[quote]
RAID 10
RAID 1+0 (or 10) is a mirrored data set (RAID 1) which is then striped
(RAID 0), hence the "1+0" name. A RAID 1+0 array requires a minimum of
four drives: two mirrored drives to hold half of the striped data,
plus another two mirrored for the other half of the data. In Linux MD
RAID 10 is a non-nested RAID type like RAID 1, that only requires a
minimum of two drives, and may give read performance on the level of
RAID 0.
[quote]

I'll read that howto, is for fakeRAID though...

TIA

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