Re: Linux Software RAID a bit of a weakness?

[berk walker <berk@panix.com>]

David Rees wrote:
> On 2/25/07, Richard Scobie <richard@sauce.co.nz> wrote:
>> Colin Simpson wrote:
>> > They therefore do not have the "check" option in the kernel. Is there
>> > anything else I can do? Would forcing a resync achieve the same result
>> > (or is that down right dangerous as the array is not considered
>> > consistent for a while). Any thoughts apart from my one being to 
>> upgrade
>> > them to RH5 when that appears with a probably 2.6.18 kernel (which 
>> will
>> > presumably have "check")? Any thoughts?
>>
>> You could configure smartd to do regular long selftests, which would
>> notify you on failures and allow you to take the drive offline and dd,
>> replace etc.
>
> So what do you do when your drives in your array don't support SMART
> self tests for some reason?
>
> The best solution I have thought of so far is to do a `dd if=/dev/mdX
> of=/dev/null` periodically, but this isn't as nice as running a check
> in the later kernels as it's not guaranteed to read blocks from all
> disks. I guess you could instead do the same thing but with the
> underlying disks instead of the raid device, then make sure you watch
> the logs for disk read errors.
>
> -Dave
> -
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> Doing a dd to each drive always seemed to work for me
> .

b-