[linux-lvm] RAID10 striping vs LVM striping over RAID1 (noob)

[hansbkk at gmail.com]

On Sun, Nov 28, 2010 at 9:29 PM, Mikael Abrahamsson <swmike at swm.pp.se> wrote:

>striping in lvm is something I wouldn't do.

Aren't you "striping in LVM" as soon as you have a VG spanning
multiple PVs anyway? I guess you mean don't bother with the
  >> should I "help" it by created multiple PVs by slicing the disks
up into partitions
question in my OP?

I've seen comments in multiple reliable places that the striping
inherent in LVM will give performance increases comparable to RAID's,
and no suggestions that it isn't as stable.


> Go for the raid10 approach per drive size and then vg them together if you really want a bigger fs, otherwise keep them as separate vg:s and you won't run into case of losing all data at once if one md fails.

Actually I want to keep the LVs containing backup data on a completely
separate set of spindles from the data being backed up, and definitely
want to just mirror the discs to enable offsite rotation and easy
disaster recovery. My understanding is that putting RAID10 on a single
pair of disks is A- in effect the same as RAID1 in the event one of
the drives fails but B- that there might be a performance boost  in
normal operations from the striping feature?

And yes that's another question - feedback from anyone welcome. . .

> I'd say "keep it simple". CPU won't be a problem, even with several
> generation old CPUs and doing raid6.
>
> mdadm does raid6 just fine, so you should consider if it suits you.
>
> If you still want to go with raid10, then you can do so, best is to not
> complicate things too much,

Thanks Mikael, yes simplicity is critical to "ease of recovery",
especially given my noobness. Are you saying RAID6 is "simpler" than
RAID10? Actually your reminder of KISS is nudging me to straight
RAID1, maybe even drop the LVM.

Actually this gives me another idea, but unrelated enough I'll start a
new thread. . .