[Durham] SMART errors

[Oliver Burnett-Hall]

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On 9 November 2014 16:09:00 GMT+00:00, David Leggett <david+lists+durhamlog at asguard.org.uk> wrote:
>
>The disk is dead, you should replace it.

Thought so.

>You can pull out all the smart details from a disk by doing
>smarctl -a /dev/sd?
>and you can tun some tests by doing
>smartctl -t long /dev/sd?
>or
>smartctl -t short /dev/sd?
>
>The test will run in the background on the disk controller.
>Once the test is finished you can get the results of the last few tests
>by
>doing
>smartctl -l selftest /dev/sda

This is where I'm getting confused: I've run those tests but they are not reporting any errors.

>Looks like you are definitely running a 2 disk raid 1 here..
>MD will have noticed the read errors from the broken disk and evicted
>it from
>the array.
>I assume these are 2TB disks, in which case yes you have a 2 disk raid
>1, if
>it was a 3 disk raid5 the capacity should be showing ~4TB.

Yes, these are 2TB disks. Like you say, the three disks set up as RAID5 would have given a capacity of 4TB. I thought that if you have a single disk fail in RAID5 you'd still keep the same capacity, just without any redundancy and with the risk of things going horribly wrong if another disk fails. Instead I appear to have lost half my capacity.

This didn't appear to have caused any problems, I'd set up md0 as a physical volume for LVM and was only using 1.5TB.

Hmmm, I wonder if I could have messed up setting this up and created a three disk RAID1 array by mistake?

Time to do some more digging...

- --
— olly
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