[Werner Reisberger]
> I am wondering if there is a possibility to use RAID 0 and RAID 1 together,
> i. e. mirroring two RAID 0 devices?
Absolutely. The most common setup appears to be:
drives 1+2: md0 (raid0)
drives 3+4: md1 (raid0)
md0+md1: md2 (raid1)
> Two general questions:
>
> - Are there any instructions for the new raidtools what to do in cases
> of disk or power failures? I only found partial outdated hints in the old
> HOWTO.
the new howto should cover it well (now in the LDP, at
http://linuxdoc.org/HOWTO/Software-RAID-HOWTO.html), but for the above
scenario, the failing drive should take down the appropriate md device
(md0 or md1) and then the md2 device should fall into degraded mode.
Regular recovery techniques (sections 5 and 6 cover them well) to get
the supporting raid0 device's drive replaced and the device re-mkraid'ed,
then raidhotadd to bring back md2.
Recovery is a tad simpler with raid1 done at the lower level simply
because none of the md device ever "dies", just one falls into degraded
and you can skip an mkraid and let normal recovery take over. Of course,
that leaves the raid1 read balancing algorithm (arguably the weak point in
the read performance of 0+1 or 1+0) running in two places instead of one.
Probably a common enough request to warrant a howto subsection :)
> - Is there an archive for this mailing list? If not I could set up one.
http://www.mail-archive.com/[email protected]/
James
