Thanks Munir, lots of useful info.

This is mdadm 1.2, and the RAID /is/ rebuilding (or, well, 
initial-building). I'll try to let it do that before I reboot for more 
testing. Only 600 minutes to go...

On Thu, 21 Mar 2013, Munir Nassar wrote:

> on modern systems there is little need for an mdadm.conf to configure the
> array.
> a couple of things to look for,
> if you are using linux-md/partitions, are the partitions marked linux raid
> autodetect? if not, then you may want to so that you do so that the linux
> kernel can build the array automatically.(note that do not below, but i also
> have an entry in mdadm.conf) 
> ARRAY /dev/md/datastore metadata=1.2
> UUID=ce33ff1a:82c18dff:ef8d5149:60e9281e name=snakeman:datastore
> 
> you can get the UUID from the mdadm command below
> 
> also, what is the md version that you are using? you can use mdadm --detail
> to find out:
> $ sudo /sbin/mdadm --detail /dev/md127
> /dev/md127:
>         Version : 1.2
>   Creation Time : Sat May 26 17:55:25 2012
>      Raid Level : raid5
>      Array Size : 5128012288 (4890.45 GiB 5251.08 GB)
>   Used Dev Size : 732573184 (698.64 GiB 750.15 GB)
>    Raid Devices : 8
>   Total Devices : 8
>     Persistence : Superblock is persistent
> 
>     Update Time : Thu Mar 21 10:23:59 2013
>           State : clean
>  Active Devices : 8
> Working Devices : 8
>  Failed Devices : 0
>   Spare Devices : 0
> 
>          Layout : left-symmetric
>      Chunk Size : 512K
> 
>            Name : snakeman:datastore  (local to host snakeman)
>            UUID : ce33ff1a:82c18dff:ef8d5149:60e9281e
>          Events : 2114
> 
>     Number   Major   Minor   RaidDevice State
>        0       8        0        0      active sync   /dev/sda
>        1       8       16        1      active sync   /dev/sdb
>        2       8       32        2      active sync   /dev/sdc
>        3       8       48        3      active sync   /dev/sdd
>        4       8       64        4      active sync   /dev/sde
>        5       8       80        5      active sync   /dev/sdf
>        9       8       96        6      active sync   /dev/sdg
>        8       8      112        7      active sync   /dev/sdh
> 
> also, does the array finish building before you reboot? /proc/mdstat should
> show you the status of the rebuild, do not power down the system before it
> has finished rebuilding.
> 
> finally, check the smart status on the drives, it could be that one of the
> drives is failing without you even knowing it, check with smartctl -a
> /dev/sdX, maybe run a long scan on each drive in turn: smartctl -t long
> /dev/sdX
> 
> 
> 
> On Thu, Mar 21, 2013 at 9:57 AM, Yaron <tclug at freakzilla.com> wrote:
>       There are no commented out options that indicate delaying mdadm,
>       but I will try and google for that.
>
>       On Thu, 21 Mar 2013, gregrwm wrote:
>
>       could be that mdadm.conf ought to wait for an event it
>       isn't waiting for
> 
> 
> 
> 
> 
> --
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> 
> 
>



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