1 May
2013
1 May
'13
2:06 p.m.
I have just had two drives failed in a server today. One is mostly part of a RAID0 set
(which is in turn part of a DRBD, so we're still good) and a small partition that is
part of a RAID1, which hasn't been failed (errors are about 1.3TB along a 2TB disk).
The other is one I was testing, it wasn't particularly new and doesn't really
matter.
Both drives have logged read errors under Linux kernel, both report drive is healthy
status (SMART overall-health self-assessment test result: PASSED), and both say
"Completed: read failure" almost immediately when I do a SMART self test (short
test or long).
I don't really have any trouble with the fact that two drives have failed, but I'm
really surprised that SMART still reports that the drive is good when it is clearly not...
what's with that?
James
1 May
1 May
9:25 p.m.
On 01/05/2013, at 3:06 PM, James Harper <james.harper(a)bendigoit.com.au> wrote:
Both drives have logged read errors under Linux
kernel, both report drive is healthy status (SMART overall-health self-assessment test
result: PASSED), and both say "Completed: read failure" almost immediately when
I do a SMART self test (short test or long).
Have you tried the same test with the drives in another machine?
Are they under warranty? Can't speak for all manufacturers, but HP drives I've had
fail in self-testing were replaced immediately under warranty.
2 May
2 May
12:18 a.m.
On 01/05/2013, at 3:06 PM, James Harper
<james.harper(a)bendigoit.com.au> wrote:
Not yet. Will be doing this shortly.
Both drives have logged read errors under Linux
kernel, both report drive is
healthy status (SMART overall-health self-assessment test result: PASSED),
and both say "Completed: read failure" almost immediately when I do a
SMART self test (short test or long).
Have you tried the same test with the drives in another machine? Are they under warranty? Can't speak for all
manufacturers, but HP drives
I've had fail in self-testing were replaced immediately under warranty.
They are Seagate ES drives, so designed for 24x7 use. Not sure how long the explicit
warranty is, but the consumer guarantee should ensure I get a replacement even if the part
only has a 1 year written warranty. No harddisk manufacturer is going to argue that their
product shouldn't reasonably be expected to last 3 years. Of course if it takes me
more than an hour of time to chase the warranty it isn't worth it - disk is only
around $250.
Last time we had a customer with a failed Seagate harddisk I recommended they buy a new
one then pursue the warranty (which is what I'm doing) as the warranty can take ages.
Turns out the warranty turnaround was days, not weeks like I thought it would be, so I was
impressed. Buying a new disk was still the faster option to ensure redundancy though.
James
12:29 a.m.
James Harper writes:
Both drives have logged read errors under Linux
kernel, both report
drive is healthy status (SMART overall-health self-assessment test
result: PASSED), and both say "Completed: read failure" almost
immediately when I do a SMART self test (short test or long).
I don't trust the "overall health".
If a short or long test fails, I chuck the drive.
1:13 a.m.
James Harper writes:
Of course. I'm just surprised that a self test can fail yet the drive still report
itself as healthy.
James
Both drives have logged read errors under Linux
kernel, both report
drive is healthy status (SMART overall-health self-assessment test
result: PASSED), and both say "Completed: read failure" almost
immediately when I do a SMART self test (short test or long).
I don't trust the "overall health".
If a short or long test fails, I chuck the drive.
2:22 a.m.
Hi,
On 2/05/2013 12:06 AM, James Harper wrote:
I have just had two drives failed in a server today.
One is mostly part of a RAID0 set (which is in turn part of a DRBD, so we're still
good) and a small partition that is part of a RAID1, which hasn't been failed (errors
are about 1.3TB along a 2TB disk). The other is one I was testing, it wasn't
particularly new and doesn't really matter.
Both drives have logged read errors under Linux kernel, both report drive is healthy
status (SMART overall-health self-assessment test result: PASSED), and both say
"Completed: read failure" almost immediately when I do a SMART self test (short
test or long).
I don't really have any trouble with the fact that two drives have failed, but
I'm really surprised that SMART still reports that the drive is good when it is
clearly not... what's with that?
This from Google:
"Our analysis identifies several parameters from the drive’s
self monitoring facility (SMART) that correlate highly with
failures. Despite this high correlation, we conclude that mod-
els based on SMART parameters alone are unlikely to be useful
for predicting individual drive failures. Surprisingly, we found
that temperature and activity levels were much less correlated
with drive failures than previously reported."
In a nutshell, SMART is not a good indicator of pending failure ... use
it as an indication only, but certainly don't count on it. But really,
SMART is next to useless overall, so it isn't even much of a "real"
indicator.... YMMV.
https://static.googleusercontent.com/external_content/untrusted_dlcp/resear…
Cheers
AndrewM
2:53 a.m.
Hi,
On 2/05/2013 12:06 AM, James Harper wrote:
It's frustrating because a simple "if hard read errors > 0 || failed self
tests > 0 then drive = not okay" would have meant I could just read the SMART
health indicator and eject the drive from the array (or whatever it belonged to).
James
I have just had two drives failed in a server
today. One is mostly part of a
RAID0 set (which is in turn part of a DRBD, so
we're still good) and a small
partition that is part of a RAID1, which hasn't been failed (errors are about
1.3TB along a 2TB disk). The other is one I was testing, it wasn't particularly
new and doesn't really matter.
Both drives have logged read errors under Linux kernel, both report drive is
healthy status (SMART overall-health self-assessment test result: PASSED),
and both say "Completed: read failure" almost immediately when I do a
SMART self test (short test or long).
I don't really have any trouble with the fact that two drives have failed, but
I'm really surprised that SMART still reports that the drive is good when it is
clearly not... what's with that?
This from Google:
"Our analysis identifies several parameters from the drive's
self monitoring facility (SMART) that correlate highly with
failures. Despite this high correlation, we conclude that mod-
els based on SMART parameters alone are unlikely to be useful
for predicting individual drive failures. Surprisingly, we found
that temperature and activity levels were much less correlated
with drive failures than previously reported."
In a nutshell, SMART is not a good indicator of pending failure ... use
it as an indication only, but certainly don't count on it. But really,
SMART is next to useless overall, so it isn't even much of a "real"
indicator.... YMMV.
4:13 a.m.
James Harper <james.harper(a)bendigoit.com.au>
writes:
It's frustrating because a simple "if hard
read errors > 0 || failed
self tests > 0 then drive = not okay" would have meant I could just
read the SMART health indicator and eject the drive from the array (or
whatever it belonged to).
IIRC from heterogeneous disks in an array I had once, I was getting 10*
the number of errors on one pair of disks from the other pair. It
turned out that seagate was reporting uncorrectable errors and WD was
reporting all errors -- the seagate had an extra field where it reported
the raw error rate.
If you are gonna script a "not okay" heuristic, be careful not to
overgeneralize from one vendor to the next.
4:25 a.m.
James Harper <james.harper(a)bendigoit.com.au>
writes:
That's why I want the vendors to make the leap that "unrecoverable read error =
unhealthy disk". The reported counters are not reliable, as you say.
James
It's frustrating because a simple "if
hard read errors > 0 || failed
self tests > 0 then drive = not okay" would have meant I could just
read the SMART health indicator and eject the drive from the array (or
whatever it belonged to).
IIRC from heterogeneous disks in an array I had once, I was getting 10*
the number of errors on one pair of disks from the other pair. It
turned out that seagate was reporting uncorrectable errors and WD was
reporting all errors -- the seagate had an extra field where it reported
the raw error rate.
If you are gonna script a "not okay" heuristic, be careful not to
overgeneralize from one vendor to the next.
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8 comments
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