Re: How to force stopping an array`

[Justin Piszcz <jpiszcz@lucidpixels.com>]

On Tue, 27 May 2008, Dexter Filmore wrote:

> Am Dienstag, 27. Mai 2008 02:05:36 schrieb NeilBrown:
>> On Tue, May 27, 2008 9:02 am, Dexter Filmore wrote:
>>> Am Dienstag, 27. Mai 2008 00:30:26 schrieb Justin Piszcz:
>>>> On Tue, 27 May 2008, Dexter Filmore wrote:
>>>>> Am Dienstag, 27. Mai 2008 00:06:57 schrieb Justin Piszcz:
>>>>>> On Mon, 26 May 2008, Dexter Filmore wrote:
>>>>>>> So I have a filesystem on an array I cannot unmount, hence I cannot
>>>>>>> stop the array.
>>>>>>> Any way to force it?
>>>>>>>
>>>>>>> Dex
>>>>>>
>>>>>> What is using it?
>>>>>>
>>>>>> lsof | grep /mount_point
>>>>>> lsof | grep /dev/mdX
>>>>>
>>>>> A defunct java process that died from a mem heap error. I can't kill
>>>>
>>>> the
>>>>
>>>>> process, not even -9, leaves a <defunct>.
>>>>
>>>> Other than rebooting I am not sure..  You could try making / re-mounting
>>>> it as read-only but if the java process is still reading from the FS it
>>>> probably will not be of any help.
>>>>
>>>> Justin.
>>>
>>> Exactly. reboot pretty much deosn't do any good, afterwars the raid
>>> resyncs,
>>> which takes full 7h here.
>>
>> There shouldn't be a resync.  Presumably nothing is writing to the
>> array, and moments after the last write, the array will have been
>> flagged as 'clean' and will not require a resync after a reboot.
                                              ^^^^^^^^^^^^^^^^^^^^^^

His host crashed != reboot so that is the reason for the resync.

>
> Well, that's what I thought. Actually the "shutdown" didn't work at all, it
> got stuck and wouldn't finish so I had to resort to Alt-SysRq-S/U/B to
> reboot.
> S/U should have ensured the file systems are in sync, but I don't know how the
> array takes to such measures. After the reboot the mdstat looks...
>>
>>> What happens there anyway? it resyncs, but mdstats say [UUUUU], all fine.
>>
>> I don't understand this question.
>>
>
> ...like this:
>
> # cat /proc/mdstat
> Personalities : [raid6] [raid5] [raid4]
> md0 : active raid5 sde1[0] sdb1[4] sdd1[3] sda1[2] sdc1[1]
>      1953503488 blocks level 5, 64k chunk, algorithm 2 [5/5] [UUUUU]
>      [>....................]  resync =  2.9% (14600832/488375872)
> finish=360.6min speed=21896K/sec
>
> unused devices: <none>
>

Justin.