Re: very large mount time after unxepected power down

["Сергей Александров" <splavgm-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

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Александров Сергей Васильевич


2012/10/30 Vyacheslav Dubeyko <slava-yeENwD64cLxBDgjK7y7TUQ@public.gmane.org>:
> Hi,
>
> On Tue, 2012-10-30 at 16:20 +0300, Сергей Александров wrote:
>> Good time of the day!
>>
>> I'v got a nilfs2 partition on a 1TB md RAID1 partition composed of two
>> HDD's. Kernel 3.5.3, userspace utils v2.1.1. Gentoo linux
>> distribution.
>> Just updated utils to 2.1.4 but no failure since.
>>
>> After power shutdown, mount takes about several hours.
>>
>
> What about RAID1 consistency? Could you describe more about your RAID
> configuration?

# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md0 : active raid1 sdb1[0] sdc1[2]
      976760400 blocks super 1.2 [2/2] [UU]

So, raid is consistent. Reading speed from md device is about 60MB/s
according to iostat.

>> For the first time I thought that it won't mount at all and tried to
>> use fsck tool, found somewhere in the internet(don't really remember).
>> It reported that superblock is ok.
>
> So, I am implementing the fsck tool for NILFS2. I guess that you take
> sources from NILFS2 e-mail list.
>
>> Than I commented the check in the source file and the default number
>> of blocks to check appeared to be too small. It failed to find the
>> next superblock. I've increased the number, but increasing it to *100
>> didn't help.
>
> Sorry, I can't understand about what sources you are talking. Could you
> describe more details about what and where you commented?
>
I've forced test_latest_log to return negative result. And changed
MAX_SCAN_SEGMENTS to 100000
That was not enough. It finished without finding the SB.


The load from fsck was the same as from mount.
About 60MB/s read from md device and about 30% load on one core.

>> So, probably the reserved SB is too far from away and it takes too
>> long to find it.
>>
>
> If you try to find the second superblock then it is placed in the begin
> of last 4 KB of the volume. Your device size is 1000202649600 bytes.
>
>> Does anybody knows, how can it be speed up? I know, UPS is a solution,
>> but I consider it be a bug.
>>
>
> Could you share more details about situation during mount operations? I
> mean: (1) NILFS2-related messages in the system log; (2) "ps ax" output;
> (3) maybe "top" output can be useful also; (4) "mount" output before
> trying to mount NILFS2 volume.
last situation:

messages log:
Oct 30 12:18:52 router kernel: [  159.674579] NILFS warning: mounting
unchecked fs
.....
.....
Oct 30 13:03:06 router kernel: [ 2810.304245] NILFS: recovery complete.
Oct 30 13:03:06 router kernel: [ 2810.325240] segctord starting.
Construction interval = 5 seconds, CP frequency < 30 seconds
Oct 30 13:03:07 router nilfs_cleanerd[15453]: start
Oct 30 13:03:07 router nilfs_cleanerd[15453]: pause (clean check)

It took about 45 minutes.
Previous time it took more than 4 hours.
Both times RAID was consistent.

top showed one process eating about 27% of cpu (2 cores, AMD Athon II
X2 250 @3000MHz)
Also, about 80% of memory is used for cache.
Sory, have not saved ps output...

I can repeat the situation if it helps.

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Aleksandrov Sergey Vasil'evich
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