[mythtv-users] Reassemble RAID with mdadm

[Brent Bolin]

On Tue, Mar 16, 2010 at 2:04 PM, Brent Bolin <brent.bolin at gmail.com> wrote:
> 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.
>

I would add to this that I have Myth  logging set to /dev/null