Re: [gentoo-user] A drive in my RAID6 has failed

[Paul Hartman]

On Thu, Sep 5, 2013 at 12:11 PM, Paul Hartman
<paul.hartman+gentoo@×××××.com> wrote:
> On Thu, Sep 5, 2013 at 11:52 AM, Michael Orlitzky <michael@××××××××.com> wrote:
>> This is the process I always follow:
>>
>>   http://www.howtoforge.com/replacing_hard_disks_in_a_raid1_array
>>
>> The sfdisk trick will save you a bit of hassle.
>
> Thanks, it looks like I was on the right path! Crossing my fingers...

So, I probably should not have attempted to do this immediately after
eating dinner. My brain was not operating at full speed, and I went
ahead and pulled the drive before removing it from the array. Oops! As
soon as I pulled the latch to release the drive, I had that "oh no!"
moment. Luckily, as it turns out, md (or mdadm? or udev?) was nice
enough to automatically remove it for me when the drive ceased to
exist.

So, I simply inserted and partitioned the new drive, added it to the
array and away we go!

md0 : active raid6 sde1[6] sdd1[5] sdg1[4] sdh1[2] sdf1[1] sdi1[0]
      11720009728 blocks super 1.2 level 6, 512k chunk, algorithm 2
[6/5] [UUU_UU]
      [>....................]  recovery =  2.3% (69513216/2930002432)
finish=428.7min speed=111206K/sec

When I wake up in the morning, I hope there won't be any errors.


BTW -- a couple tips I found which speed up RAID building/recovery
tremendously (season to taste):

echo 32768 > /sys/block/md0/md/stripe_cache_size
echo 200000 > /proc/sys/dev/raid/speed_limit_max