[mythtv-users] Reassemble RAID with mdadm

[Brent Bolin]

On Tue, Mar 16, 2010 at 12:03 PM, MarcT <myrdhn at gmail.com> wrote:
> Steve,
>
> Here is the current status of my raid -
>
> mdadm -D /dev/md0
> /dev/md0:
>        Version : 00.90
>  Creation Time : Mon Dec 14 19:17:08 2009
>     Raid Level : raid1
>     Array Size : 976759936 (931.51 GiB 1000.20 GB)
>  Used Dev Size : 976759936 (931.51 GiB 1000.20 GB)
>   Raid Devices : 2
>  Total Devices : 2
> Preferred Minor : 0
>    Persistence : Superblock is persistent
>
>    Update Time : Tue Mar 16 09:00:38 2010
>          State : clean
>  Active Devices : 2
> Working Devices : 2
>  Failed Devices : 0
>  Spare Devices : 0
>
>           UUID : d376cfd0:a438be3c:5f1e94b5:d63edfe3 (local to host myth)
>         Events : 0.283797
>
>    Number   Major   Minor   RaidDevice State
>       0       8       17        0      active sync   /dev/sdb1
>       1       8       33        1      active sync   /dev/sdc1
>
> So if the status ever changes to degraded(not sure what it would
> change to if bad sectors etc...) could I simply bring the box down and
> replace with another drive?  I don't have any spares defined trying to
> keep power usage as low as possible.
>
> Or is there an added set of commands to run when the bad drive is replaced?
> _______________________________________________
>
> Mirroring is fine for fault tolerance, but you get no speed boost from it.
> I would recommend getting 2 more drives if you can afford it and setup a
> RAID5 configuration.
> Not only do you get a fault tolerant array, can lose 1 drive and not lose
> data, but you get a speed boost because the system writes data across all
> the drives.
>
> MarcT
>
>
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>

Believe you can do a raid5 configuration with 3 drives.  However
generating the parity bit slows things down on the write.

With 4 drives you would be better using RAID 0+1

Currently see no bottleneck using raid1.  That's recording 4 HD
channels at a time.  Flagging set for medium using 2 instances.  And
often times running a single Handbrake rip.

Never really did get an answer to my question.  But from a little
googling looks like a failing drive would need to be removed.  And
then a replacement drive added.