On Tue Nov 01, 2011 at 04:13:26 -0400, Miles Fidelman wrote:
> David Brown wrote:
> >
> > No, md RAID10 does /not/ offer more redundancy than RAID1. You are
> > right that md RAID10 offers more than RAID1 (or traditional RAID0 over
> > RAID1 sets) - but it is a convenience and performance benefit, not a
> > redundancy benefit. In particular, it lets you build RAID10 from any
> > number of disks, not just two. And it lets you stripe over all disks,
> > improving performance for some loads (though not /all/ loads - if you
> > have lots of concurrent small reads, you may be faster using plain
> > RAID1).
>
> wasn't suggesting that it does - just that it does things differently
> than normal raid 1+0 - for example, by doing mirroring and striping as a
> unitary operation, it works across odd number of drives - it also (I
> think) allows for more than 2 copies of a block (not completely clear
> how many copies of a block would be made if you specified a 16 drive
> array) - sort of what I'm wondering here
>
By default it'll make 2 copies, regardless how many devices are in the
array. You can specify how many copies you want though, so -n3 will give
you a near configuration with 3 copies, -n4 for four copies, etc.
Cheers,
Robin
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( ' } | Robin Hill <robin@xxxxxxxxxxxxxxx> |
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