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

Дмитрий Глушенок glush at jet.msk.su
Wed Aug 17 10:18:51 UTC 2016


Unfortunately not:

Remount FS, then access test file from second client:

[root at srv02 ~]# umount /mnt
[root at srv02 ~]# mount -t glusterfs srv01:/test01 /mnt
[root at srv02 ~]# ls -l /mnt/passwd 
-rw-r--r--. 1 root root 1505 авг 16 19:59 /mnt/passwd
[root at srv02 ~]# ls -l /R1/test01/
итого 4
-rw-r--r--. 2 root root 1505 авг 16 19:59 passwd
[root at srv02 ~]# 

Then remount FS and check if accessing the file from second node triggered self-heal on first node:

[root at srv01 ~]# umount /mnt
[root at srv01 ~]# mount -t glusterfs srv01:/test01 /mnt
[root at srv01 ~]# ls -l /mnt
итого 0
[root at srv01 ~]# ls -l /R1/test01/
итого 0
[root at srv01 ~]#

Nothing appeared.

[root at srv01 ~]# gluster volume info test01
 
Volume Name: test01
Type: Replicate
Volume ID: 2c227085-0b06-4804-805c-ea9c1bb11d8b
Status: Started
Number of Bricks: 1 x 2 = 2
Transport-type: tcp
Bricks:
Brick1: srv01:/R1/test01
Brick2: srv02:/R1/test01
Options Reconfigured:
features.scrub-freq: hourly
features.scrub: Active
features.bitrot: on
transport.address-family: inet
performance.readdir-ahead: on
nfs.disable: on
[root at srv01 ~]# 

[root at srv01 ~]# gluster volume get test01 all | grep heal
cluster.background-self-heal-count      8                                       
cluster.metadata-self-heal              on                                      
cluster.data-self-heal                  on                                      
cluster.entry-self-heal                 on                                      
cluster.self-heal-daemon                on                                      
cluster.heal-timeout                    600                                     
cluster.self-heal-window-size           1                                       
cluster.data-self-heal-algorithm        (null)                                  
cluster.self-heal-readdir-size          1KB                                     
cluster.heal-wait-queue-length          128                                     
features.lock-heal                      off                                     
features.lock-heal                      off                                     
storage.health-check-interval           30                                      
features.ctr_lookupheal_link_timeout    300                                     
features.ctr_lookupheal_inode_timeout   300                                     
cluster.disperse-self-heal-daemon       enable                                  
disperse.background-heals               8                                       
disperse.heal-wait-qlength              128                                     
cluster.heal-timeout                    600                                     
cluster.granular-entry-heal             no                                      
[root at srv01 ~]#

--
Dmitry Glushenok
Jet Infosystems

> 17 авг. 2016 г., в 11:30, Ravishankar N <ravishankar at redhat.com> написал(а):
> 
> 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 <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
>>>> 
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>>>> http://www.gluster.org/mailman/listinfo/gluster-users <http://www.gluster.org/mailman/listinfo/gluster-users>
> 

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