[mythtv-users] LVM RAID 5 partition schemes

[Dan Christensen]

David <myth at dgreaves.com> writes:

> Finally, there is a complex idea suggested by Dan Christensen:
>
> Create multiple partitions on each device:
> sda1,sda2,sda3,sda4
> sdb1,sdb2,sdb3,sdb4
> etc
>
> create 1 raid5 device for each partition
> md0=sda1+sdb1+sdc1
> md1=sda2+sdb2+sdc2
>
> finally lvm all these together.
>
> now to add a drive you must:
> * add a backup device to the lvm
> for each md device
> * lvm move the blocks of 1 md device to a backup device
> * remove md device from lvm
> * destroy + rebuild the md device
> * add back to lvm
> * lvm move the blocks of the backup device
> * remove backup device from lvm

Ah, that's more detailed than I had worked out, which is why I didn't
recognize the summary of it you had given!  :-)  I didn't even know
lvm had a move option.

> Dan's solution (proper credit!) 

You mean David's solution?  :-)

> is probably the safest but is time consuming and possibly
> human-error prone.

I might try the above, but substituting raidreconf for the
destroy/rebuild/lvm move steps.  Or I might just use raidreconf
without a backup (after reading the kernel-raid archives, as you
suggested...) 

Thanks for the ideas!

Dan