[Gluster-users] 3.7.13, index healing broken?

Wed Jul 13 04:46:41 UTC 2016

On Wed, Jul 13, 2016 at 10:10 AM, Dmitry Melekhov <dm at belkam.com> wrote:

> 13.07.2016 08:36, Pranith Kumar Karampuri пишет:
>
>
>
> On Wed, Jul 13, 2016 at 9:35 AM, Dmitry Melekhov < <dm at belkam.com>
> dm at belkam.com> wrote:
>
>> 13.07.2016 01:52, Anuradha Talur пишет:
>>
>>>
>>> ----- Original Message -----
>>>
>>>> From: "Dmitry Melekhov" < <dm at belkam.com>dm at belkam.com>
>>>> To: "Pranith Kumar Karampuri" < <pkarampu at redhat.com>
>>>> pkarampu at redhat.com>
>>>> Cc: "gluster-users" <gluster-users at gluster.org>
>>>> Sent: Tuesday, July 12, 2016 9:27:17 PM
>>>> Subject: Re: [Gluster-users] 3.7.13, index healing broken?
>>>>
>>>>
>>>>
>>>> 12.07.2016 17:39, Pranith Kumar Karampuri пишет:
>>>>
>>>>
>>>>
>>>> Wow, what are the steps to recreate the problem?
>>>>
>>>> just set file length to zero, always reproducible.
>>>>
>>>> If you are setting the file length to 0 on one of the bricks (looks like
>>> that is the case), it is not a bug.
>>>
>>> Index heal relies on failures seen from the mount point(s)
>>> to identify the files that need heal. It won't be able to recognize any
>>> file
>>> modification done directly on bricks. Same goes for heal info command
>>> which
>>> is the reason heal info also shows 0 entries.
>>>
>>
>> Well, this makes self-heal useless then- if any file is accidently
>> corrupted or deleted (yes! if file is deleted directly from brick this is
>> no recognized by idex heal too), then it will not be self-healed, because
>> self-heal uses index heal.
>>
>
> It is better to look into bit-rot feature if you want to guard against
> these kinds of problems.
>
>
> Bit rot detects bit problems, not missing files or their wrong length,
> i.e. this is overhead for such simple task.
>

It detects wrong length. Because checksum won't match anymore.

What use-case you are trying out is leading to changing things directly on
the brick?

>
> Thank you!
>
>
>
>
>>
>>
>>> Heal full on the other hand will individually compare certain aspects of
>>> all
>>> files/dir to identify files to be healed. This is why heal full works in
>>> this case
>>> but index heal doesn't.
>>>
>> OK, thank yo for explanation, but , once again how about self-healing and
>> data consistency?
>> And, if I access this deleted or broken file from client then it will be
>> healed, I guess this is what self-heal needs to do.
>>
>> Thank you!
>>
>>
>>
>>>>
>>>>
>>>> On Tue, Jul 12, 2016 at 3:09 PM, Dmitry Melekhov < dm at belkam.com >
>>>> wrote:
>>>>
>>>>
>>>>
>>>> 12.07.2016 13:33, Pranith Kumar Karampuri пишет:
>>>>
>>>>
>>>>
>>>> What was "gluster volume heal <volname> info" showing when you saw this
>>>> issue?
>>>>
>>>> just reproduced :
>>>>
>>>>
>>>> [root at father brick]# > gstatus-0.64-3.el7.x86_64.rpm
>>>>
>>>> [root at father brick]# gluster volume heal pool
>>>> Launching heal operation to perform index self heal on volume pool has
>>>> been
>>>> successful
>>>> Use heal info commands to check status
>>>> [root at father brick]# gluster volume heal pool info
>>>> Brick father:/wall/pool/brick
>>>> Status: Connected
>>>> Number of entries: 0
>>>>
>>>> Brick son:/wall/pool/brick
>>>> Status: Connected
>>>> Number of entries: 0
>>>>
>>>> Brick spirit:/wall/pool/brick
>>>> Status: Connected
>>>> Number of entries: 0
>>>>
>>>> [root at father brick]#
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Mon, Jul 11, 2016 at 3:28 PM, Dmitry Melekhov < dm at belkam.com >
>>>> wrote:
>>>>
>>>>
>>>> Hello!
>>>>
>>>> 3.7.13, 3 bricks volume.
>>>>
>>>> inside one of bricks:
>>>>
>>>> [root at father brick]# ls -l gstatus-0.64-3.el7.x86_64.rpm
>>>> -rw-r--r-- 2 root root 52268 июл 11 13:00 gstatus-0.64-3.el7.x86_64.rpm
>>>> [root at father brick]#
>>>>
>>>>
>>>> [root at father brick]# > gstatus-0.64-3.el7.x86_64.rpm
>>>> [root at father brick]# ls -l gstatus-0.64-3.el7.x86_64.rpm
>>>> -rw-r--r-- 2 root root 0 июл 11 13:54 gstatus-0.64-3.el7.x86_64.rpm
>>>> [root at father brick]#
>>>>
>>>> so now file has 0 length.
>>>>
>>>> try to heal:
>>>>
>>>>
>>>>
>>>> [root at father brick]# gluster volume heal pool
>>>> Launching heal operation to perform index self heal on volume pool has
>>>> been
>>>> successful
>>>> Use heal info commands to check status
>>>> [root at father brick]# ls -l gstatus-0.64-3.el7.x86_64.rpm
>>>> -rw-r--r-- 2 root root 0 июл 11 13:54 gstatus-0.64-3.el7.x86_64.rpm
>>>> [root at father brick]#
>>>>
>>>>
>>>> nothing!
>>>>
>>>> [root at father brick]# gluster volume heal pool full
>>>> Launching heal operation to perform full self heal on volume pool has
>>>> been
>>>> successful
>>>> Use heal info commands to check status
>>>> [root at father brick]# ls -l gstatus-0.64-3.el7.x86_64.rpm
>>>> -rw-r--r-- 2 root root 52268 июл 11 13:00 gstatus-0.64-3.el7.x86_64.rpm
>>>> [root at father brick]#
>>>>
>>>>
>>>> full heal is OK.
>>>>
>>>> But, self-heal is doing index heal according to
>>>>
>>>>
>>>> http://staged-gluster-docs.readthedocs.io/en/release3.7.0beta1/Developer-guide/afr-self-heal-daemon/
>>>>
>>>> Is this bug?
>>>>
>>>>
>>>> As far as I remember it worked in 3.7.10....
>>>>
>>>>
>>>> _______________________________________________
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>>>> Gluster-users at gluster.org
>>>> http://www.gluster.org/mailman/listinfo/gluster-users
>>>>
>>>>
>>>>
>>>> --
>>>> Pranith
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Pranith
>>>>
>>>>
>>>> _______________________________________________
>>>> Gluster-users mailing list
>>>> Gluster-users at gluster.org
>>>> http://www.gluster.org/mailman/listinfo/gluster-users
>>>>
>>>
>>
>
>
> --
> Pranith
>
>
>

-- 
Pranith
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