Re: RAID10 - Ensure mirrors aren't on same JBOD

[Michael Evans <mjevans1983@gmail.com>]

On Mon, Apr 26, 2010 at 11:57 AM, Andrew Klaassen <clawsoon@yahoo.com> wrote:
> --- On Mon, 4/26/10, Michael Evans <mjevans1983@gmail.com> wrote:
>
>> > --- On Mon, 4/26/10, Michael Evans <mjevans1983@gmail.com>
>> wrote:
>> > However, it doesn't say what happens with a larger
>> > number of drives.  I'm looking for the kind of control I
>> > can get with RAID 1+0, where I can specify which drives are
>> > mirrors of each other.  Is that possible with RAID10?
>>
>> No, not predictably; the only provided guarantee is that
>> the data will
>> /not/ be duplicated on the same block-device (usually
>> drive).  In
>> practice you will quickly be able to determine where a
>> particular
>> version with a given range of input causes data to be
>> stored, but
>> there is no requirement that future versions produce the
>> precise same
>> alignment and offsets.
>
> Ah.  So if I want this level of control, I have to sacrifice the advantages of RAID 10 and go with RAID 1+0.
>
> Good to know.  Thanks.
>
> Andrew
>
>
>
>
>
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Or write your own program to generate mdadm headers on uninitialized
devices.  Or if it's just a one time thing, write the headers, stop
the array, make sure it says what you want, and then force a resync
before writing any data.
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