On Tue, 1 Nov 2011 23:15:39 +0100 keld@xxxxxxxxxx wrote: > On Tue, Nov 01, 2011 at 04:13:26PM -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). > > In fact raid10 mas a bit less redundancy than raid1+0. > It is as far as I know built as raid0+1 with a disk layout > where you can only loose eg 1 out of 4 disks, while raid1+0 > in some cases can lose 2 disks out of 4. With md/raid10 you can in some case lose 2 out of 4 disks and survive, just like raid1+0. NeilBrown > > Also for lots of concurrent small reads raid10 can in some cases be somewhat > faster than raid1, and AFAIK never slower than raid1. > > Best regards > keld > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html
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