Neil Brown wrote:
On Thu, 20 May 2010 12:02:23 -0500
Trey Scarborough <treys@xxxxxxxxxxxxxx> wrote:
I have a raid 5 array with 9 disks and I have a mismatch_cnt that keeps
growing. This is causing file corruption on the underlaying file systems
as well. I can copy a group of 100 100mb files and then do a md5sum on
them and 1-3 will be corrupt. If this is a drive that is bad is there
anyway to run a report on the count per drive that these mismatches
occur. I have run smarttools test and do not see one drive that stands
out to be causing errors. Could something else be causing these errors?
When RAID5 detects an inconsistency there is no way to know which device was
wrong.
SMART only detects some errors, not all.
I have had hard drives before which appears to have a single-bit error in
their internal buffer. No error would be reported, but data you read would
sometimes be wrong.
RAID5 cannot help you with this sort of error.
I would suggest backing up all your data (if it isn't already to late),
breaking the array, and testing each device individually.
e.g. create a filesystem on the device and try copying data on and reading it
off.
NeilBrown
Thats what I was afraid of. The problem I have is if I back it up
knowing what data is bad. Luckily it appears to be a write error because
once written and correct I can do sums on all the files and I do not see
anymore errors. I was thinking that there might be a way of do a resync
and turning up the debug somehow so that it would log the mismatches
with both the drives that it was reading from at the time. I could then
take that information and considering there are 9 drives in the array
the one that comes out having the most should be the culprit. I could
then remove that drive from the array and test it leaving the rest in a
state that could be rebuilt and the data being consistant because the
drive with the bad write errors would be removed. Is this something that
might be possible?
Thanks,
Trey
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