Re: Issue removing failed drive and re adding on raid 6

On Sat, 4 Jul 2015, Wols Lists wrote:

On 04/07/15 07:10, Justin Stephenson wrote:

quoted

ata6.00: ATA-8: ST3000DM001-9YN166, CC4H, max UDMA/133
ata6.00: 5860533168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA
ata7.00: ATA-9: ST3000DM001-1CH166, CC27, max UDMA/133
ata7.00: 5860533168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA
ata8.00: ATA-9: ST3000DM001-1CH166, CC27, max UDMA/133
ata8.00: 5860533168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA
ata5.00: ATA-9: ST3000DM001-1CH166, CC27, max UDMA/133
ata5.00: 5860533168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA
ata6.00: configured for UDMA/133
ata4.00: ATA-9: ST3000DM001-1CH166, CC27, max UDMA/133
ata4.00: 5860533168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA

OWWWWW OWWWWWW OWWWWW

Are these 3TB Seagate Barracudas? (Same as mine). You DO NOT want to be
running raid 5 or 6 on these things !!!! They're desktop drives not
meant for raid.

Not only that, but they're known to have en extremely high failure rate:

https://www.backblaze.com/blog/3tb-hard-drive-failure/

"As of March 31, 2015, 1,423 of the 4,829 deployed Seagate 3TB drives had failed, that’s 29.5% of the drives."

Make sure you've got your raid timeout increased - there's plenty of threads about how to do it - otherwise one disk hiccup for any reason is likely to cause a cascade of failures !!!!

I recommend this as minimum (in rc.local for instance):

for x in /sys/block/sd[a-z] ; do
        echo 180  > $x/device/timeout
done

echo 4096 > /sys/block/md0/md/stripe_cache_size

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se