[mythtv-users] An LVM'd drive died! What do I do...

[Steve Adeff]

On Thursday 27 October 2005 12:42, Erik Karlin wrote:
> On Thu, Oct 27, 2005 at 05:07:50PM +0100, Alexander Fisher wrote:
> > On 10/27/05, David Bennett <davidbennett1979 at gmail.com> wrote:
> > > I must admit you have me quite intrigued by this RAID 5.
> > >
> > > So heres the deal, I am going to go out and buy some disks.
> > > Anything I need to know before I start?
> >
> > 250GB disks currently seem to give the most GB per $ or ?
> >
> > > How (and what) do I need to know to setup a software Raid 5 on my
> > > linux? Any guides etc.?
> >
> > I've had quite a bit of success installing Debian with RAID and LVM
> > configured during the install.  GRUB won't boot off RAID5 (or LVM?)
> > but it will boot off RAID1.  Therefore, I would suggest something like
> > this ...
> >
> > 3 disks sda,sdb,sdc. 3 partitions on each.
> > sd[abc]1 small (<1GB) RAID 1 (md0) formatted ext3 and used for /boot.
> > sd[abc]2 small formatted for swap.  Swap is automatically striped
> > across swap partitions.  If you don't want your system to potentially
> > crash when you have a disk failure, you can put swap over RAID 1
> > instead.
>
> I've done exactly this, though I did do a raid1 for swap too.
>
> > sd[abc]3 remaining space, RAID 5, and one LVM PV on top of this.
> > Create one VG and several LVs out of this, one for each of your other
> > filesystems (/, /usr /var/mediastore etc.)  Format these XFS but don't
> > make them bigger than they need to be, (XFS can easily grow
> > filesystems online but doesn't support shrinking).
>
> Here's where I diverge, and haven't seen mentioned yet. I went the
> raid10 route instead. with raid5, you can lose up to 1 drive in the
> array. any more and you lose the array. With raid10 you can lose half,
> in theory, as long as they're not in the same raid1 set. I've got 6x250g
> disks as 3 raid1 mirrors and then raid0 the 3 raid1 arrays.

does raid10 do parity? I thought raid 10 required a backup harddrive for every 
drive in the array?

Steve