Re: [Moosefs-users] HELP!!! 250T Data lost!

[陈钢 <yik...@gm...>]

In master`s metadata.mfs,i saw  nodes part is complete, part of names, no
free, no chunks..

2012/3/7 Davies Liu <dav...@gm...>

> Hi,
>
> I had try to recover it from metadata.mfs and metadata_ml.mfs.back, but
> failed.
>
> Because disk is full, mfsmaster had not dump all the metadata into disks,
> had part of nodes in metadata.mfs, no names, no edges, no chunks.
> No hope to recover from the broken metadata.mfs, it's too short.
>
> The changelogs are also helpless, only in two days.
>
> The only hope is try to undelete the previous metadata_ml.mfs.back from
> metalogger machine, Chenggang had also failed, with extundelete and
> etx3grep,
> maybe some experts can archive this.
>
> The final options is to GUESS the relation between files and chunks by
> chunk id and size fo files, if data lost can not been afforded. Each chunk
> is
> combined with crc checksum and real data, if we know the relation between
> files and chunksever, then we can get data back. Or we can contruct the
> metadata according to the GUESS, the using mfsmaster to recover them.
>
> Davies
>
> On Wed, Mar 7, 2012 at 10:56 AM, Ken <ken...@gm...> wrote:
>
>> Hi, chengang
>>
>> I think you should try more, and post detail here. Someone must resolve
>> it.
>> Maybe you will lost some data in last few minutes, but 250T should be
>> saved.
>>
>> At first, BACKUP all files:
>>   /var/lib/mfs/* on master
>>   /var/lib/mfs/* on mfsmetalogger
>>
>> about restore error:
>>
>> file 'metadata.mfs.back' not found - will try 'metadata_ml.mfs.back'
>>> instead
>>> loading objects (files,directories,etc.) ... loading node: read error:
>>> ENOENT (No such file or directory)
>>> error
>>> can't read metadata from file: .//metadata_ml.mfs.back
>>>
>>  How did you run mfsmetarestore?  add -d options?
>> If stat(datapath + metadata_ml.mfs.back) fail, these error will occur.
>> Maybe use strace will show why stat fail exactly.
>>
>> ps: I am in Beijing now and I can provide more help.
>>
>> HTH
>>
>> -Ken
>>
>>
>>
>> On Wed, Mar 7, 2012 at 10:21 AM, 陈钢 <yik...@gm...> wrote:
>>
>>> can not start mfsmaster with the file "78962688 Mar  6 17:18
>>> metadata.mfs "..
>>> i tried that. :(
>>>
>>> 2012/3/7 Ricardo J. Barberis <ric...@da...>
>>>
>>> El Martes 06/03/2012, 陈钢 escribió:
>>>> > on master
>>>> [ ... ]
>>>> > -rw-r-----  1 mfs  mfs   78962688 Mar  6 17:18 metadata.mfs
>>>> > -rw-r--r--  1 root root         8 Jul  4  2011 metadata.mfs.empty
>>>> > -rw-r-----  1 mfs  mfs       5984 Mar  6 12:00 sessions.mfs
>>>> > -rw-r-----  1 mfs  mfs          0 Mar  6 16:46 sessions.mfs.tmp
>>>> > -rw-r-----  1 mfs  mfs     131072 Mar  6 17:18 stats.mfs
>>>>
>>>> You have /var/lib/mfs/metadata.mfs on the master, it might not be
>>>> corrupt
>>>> after all?
>>>>
>>>> I'd suggest:
>>>>
>>>> - backup /var/lib/mfs to another disk/server (for later recovery if
>>>> needed)
>>>> - make sure you have free space in your main disk
>>>> - then simply try to start mfsmaster
>>>> - check mfs.cgi (web interface) if it looks OK
>>>>
>>>>
>>>> BUT: if you can, wait for confirmation from Michał Borychowski first,
>>>> in case
>>>> what I'm telling you is not safe.
>>>>
>>>>
>>>> (BTW: You have Reply-To set to che...@cp..., I don't know if
>>>> that's
>>>> intentional on your part)
>>>>
>>>> Hope it helps,
>>>> --
>>>> Ricardo J. Barberis
>>>> Senior SysAdmin / ITI
>>>> Dattatec.com :: Soluciones de Web Hosting
>>>> Tu Hosting hecho Simple!
>>>>
>>>> ------------------------------------------
>>>>
>>>
>>>
>>>
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>>
>>
>> ------------------------------------------------------------------------------
>> Virtualization & Cloud Management Using Capacity Planning
>> Cloud computing makes use of virtualization - but cloud computing
>> also focuses on allowing computing to be delivered as a service.
>> http://www.accelacomm.com/jaw/sfnl/114/51521223/
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>>
>
>
> --
>  - Davies
>