[Gluster-users] Self healing does not see files to heal

[Ravishankar N]

On 08/17/2016 01:48 PM, Дмитрий Глушенок wrote:
> Hello Ravi,
>
> Thank you for reply. Found bug number (for those who will google the 
> email) https://bugzilla.redhat.com/show_bug.cgi?id=1112158
>
> Accessing the removed file from mount-point is not always working 
> because we have to find a special client which DHT will point to the 
> brick with removed file. Otherwise the file will be accessed from good 
> brick and self-healing will not happen (just verified). Or by 
> accessing you meant something like touch?

Sorry should have been more explicit. I meant triggering a lookup on 
that file with `stat filename`. I don't think you need a special client. 
DHT sends the lookup to AFR which in turn sends to all its children. 
When one of them returns ENOENT (because you removed it from the brick), 
AFR will automatically trigger heal. I'm guessing it is not always 
working in your case due to caching at various levels and the lookup not 
coming till AFR. If you do it from a fresh mount ,it should always work.
-Ravi

> Dmitry Glushenok
> Jet Infosystems
>
>> 17 авг. 2016 г., в 4:24, Ravishankar N <ravishankar at redhat.com 
>> <mailto:ravishankar at redhat.com>> написал(а):
>>
>> On 08/16/2016 10:44 PM, Дмитрий Глушенок wrote:
>>> Hello,
>>>
>>> While testing healing after bitrot error it was found that self 
>>> healing cannot heal files which were manually deleted from brick. 
>>> Gluster 3.8.1:
>>>
>>> - Create volume, mount it locally and copy test file to it
>>> [root at srv01 ~]# gluster volume create test01 replica 2 
>>>  srv01:/R1/test01 srv02:/R1/test01
>>> volume create: test01: success: please start the volume to access data
>>> [root at srv01 ~]# gluster volume start test01
>>> volume start: test01: success
>>> [root at srv01 ~]# mount -t glusterfs srv01:/test01 /mnt
>>> [root at srv01 ~]# cp /etc/passwd /mnt
>>> [root at srv01 ~]# ls -l /mnt
>>> итого 2
>>> -rw-r--r--. 1 root root 1505 авг 16 19:59 passwd
>>>
>>> - Then remove test file from first brick like we have to do in case 
>>> of bitrot error in the file
>>
>> You also need to remove all hard-links to the corrupted file from the 
>> brick, including the one in the .glusterfs folder.
>> There is a bug in heal-full that prevents it from crawling all bricks 
>> of the replica. The right way to heal the corrupted files as of now 
>> is to access them from the mount-point like you did after removing 
>> the hard-links. The list of files that are corrupted can be obtained 
>> with the scrub status command.
>>
>> Hope this helps,
>> Ravi
>>
>>> [root at srv01 ~]# rm /R1/test01/passwd
>>> [root at srv01 ~]# ls -l /mnt
>>> итого 0
>>> [root at srv01 ~]#
>>>
>>> - Issue full self heal
>>> [root at srv01 ~]# gluster volume heal test01 full
>>> Launching heal operation to perform full self heal on volume test01 
>>> has been successful
>>> Use heal info commands to check status
>>> [root at srv01 ~]# tail -2 /var/log/glusterfs/glustershd.log
>>> [2016-08-16 16:59:56.483767] I [MSGID: 108026] 
>>> [afr-self-heald.c:611:afr_shd_full_healer] 0-test01-replicate-0: 
>>> starting full sweep on subvol test01-client-0
>>> [2016-08-16 16:59:56.486560] I [MSGID: 108026] 
>>> [afr-self-heald.c:621:afr_shd_full_healer] 0-test01-replicate-0: 
>>> finished full sweep on subvol test01-client-0
>>>
>>> - Now we still see no files in mount point (it becomes empty right 
>>> after removing file from the brick)
>>> [root at srv01 ~]# ls -l /mnt
>>> итого 0
>>> [root at srv01 ~]#
>>>
>>> - Then try to access file by using full name (lookup-optimize and 
>>> readdir-optimize are turned off by default). Now glusterfs shows the 
>>> file!
>>> [root at srv01 ~]# ls -l /mnt/passwd
>>> -rw-r--r--. 1 root root 1505 авг 16 19:59 /mnt/passwd
>>>
>>> - And it reappeared in the brick
>>> [root at srv01 ~]# ls -l /R1/test01/
>>> итого 4
>>> -rw-r--r--. 2 root root 1505 авг 16 19:59 passwd
>>> [root at srv01 ~]#
>>>
>>> Is it a bug or we can tell self heal to scan all files on all bricks 
>>> in the volume?
>>>
>>> --
>>> Dmitry Glushenok
>>> Jet Infosystems
>>>
>>> _______________________________________________
>>> Gluster-users mailing list
>>> Gluster-users at gluster.org <mailto:Gluster-users at gluster.org>
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>

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