On 10/9/2017 9:16 PM, Phil Turmel wrote:
On 10/07/2017 04:21 AM, Carsten Aulbert wrote:
Hi
On 10/07/17 09:48, Alexander Shenkin wrote:
My SMART monitoring has picked up some pending sectors on one of my
RAID0 + RAID5 drives (it's one of the infamous 3TB seagate drives... my
other 3 failed earlier... this is the last of them, that finally has
gone as well...). I've just ordered a replacement (Toshiba P300) that
will arrive tomorrow... but the question is, what to do in the meantime?
Should I take the drive offline? I suspect so, but would like to
double check before taking action. Thanks in advance for any advice.
Given this is "only" a single sector error I would keep it running as
long as you can physically install the new drive and only then take it
offline.
At least theoretically, it may be possible to force the rewrite of this
sector and use the spare sectors of the disk, but I'm not 100% sure if a
simple md check would already trigger it - usually you need to write
"new" data to defective sectors to force the drive's firmware to use the
spare sectors.
But given the replacement disk should arrive soon, I would not act
before that and run with a degraded RAID5 until then.
I'm a bit more worried about the RAID0 here, do you run RAID0 on top of
RAID5 or what is the exact set-up?
So, no regular "check" scrubs. Check scrubs fix pending sectors by
writing back to such sectors when the error is hit. As long as there is
redundancy to obtain the data from, and the drive in question actually
returns a read error.
Thanks... I know nothing about "check scrubs". Could you point me to a
good resource? I've found
https://raid.wiki.kernel.org/index.php/Scrubbing and
https://raid.wiki.kernel.org/index.php/Scrubbing_the_drives, but it's
hard to tell exactly how the system should be configured in order to run
these regularly. A weekly cron perhaps? And, should it be just check,
or repair? etc... Any help you could offer would be welcome.
Is this something I should run now? I figure it's a bad idea to push an
array that is starting to degrade... haven't had a chance to replace the
drive yet, but will get to it this week. Probably best to start the
scrubbing routines once I have 4 good drives in there I figure...
Since this is a desktop drive that is known to not have SCTERC support,
you *must* reset your driver timeouts to 180 seconds for a check scrub
to succeed. You will also have to do so with your P300 drive, as
Toshiba's website says that drive is not NAS optimized.
Please read up on "timeout mismatch" before your array blows up.
I have timeouts set on all drives when the system boots, and the same
script turns on the P300s' SCTERC.
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