[Gluster-users] using a preferred node ?

Ravishankar N ravishankar at redhat.com
Mon Jun 8 06:11:01 UTC 2015



On 06/08/2015 11:34 AM, Mathieu Chateau wrote:
> Hello Ravi,
>
> thanks for clearing things up.
>
> Anything on the roadmap that would help my case?
>


I don't think it would be possible for clients to do I/O only on its 
local brick and yet expect the bricks' contents to be in sync in real-time..


> Cordialement,
> Mathieu CHATEAU
> http://www.lotp.fr
>
> 2015-06-08 6:37 GMT+02:00 Ravishankar N <ravishankar at redhat.com 
> <mailto:ravishankar at redhat.com>>:
>
>
>
>     On 06/06/2015 12:49 AM, Mathieu Chateau wrote:
>>     Hello,
>>
>>     sorry to bother again but I am still facing this issue.
>>
>>     client still looks on the "other side" and not using the node
>>     declared in fstab:
>>     prd-sta-sto01:/gluster-preprod /mnt/gluster-preprod glusterfs
>>     defaults,_netdev,backupvolfile-server=prd-sta-sto02 0 0
>>
>>     I expect client to use sto01 and not sto02 as it's available.
>
>     Hi Mathieu,
>     When you do lookups (`ls` etc), they are sent to both bricks of
>     the replica. If you write to a file, the write is also sent to
>     both bricks. This is how it works. Only reads are served from the
>     local brick.
>     -Ravi
>
>
>>
>>     If I add a static route to break connectivity to sto02 and do a
>>     "df", I have around 30s before it works.
>>     Then it works ok.
>>
>>     Questions:
>>
>>       * How to force node to stick as possible with one specific
>>         (local) node ?
>>       * How to know where a client is currently connected?
>>
>>     Thanks for your help :)
>>
>>
>>     Cordialement,
>>     Mathieu CHATEAU
>>     http://www.lotp.fr
>>
>>     2015-05-11 7:26 GMT+02:00 Mathieu Chateau
>>     <mathieu.chateau at lotp.fr <mailto:mathieu.chateau at lotp.fr>>:
>>
>>         Hello,
>>
>>         thanks for helping :)
>>
>>         If gluster server is rebooted, any way to make client
>>         failback on node after reboot ?
>>
>>         How to know which node is using a client ? I see TCP
>>         connection to both node
>>
>>         Regards,
>>
>>         Cordialement,
>>         Mathieu CHATEAU
>>         http://www.lotp.fr
>>
>>         2015-05-11 7:13 GMT+02:00 Ravishankar N
>>         <ravishankar at redhat.com <mailto:ravishankar at redhat.com>>:
>>
>>
>>
>>             On 05/10/2015 08:29 PM, Mathieu Chateau wrote:
>>>             Hello,
>>>
>>>             Short way: Is there any way to define a preferred
>>>             Gluster server ?
>>>
>>>             Long way:
>>>             I have the following setup (version 3.6.3) :
>>>
>>>             Gluster A  <==> VPN <==> Gluster B
>>>
>>>             Volume is replicated between A and B.
>>>
>>>             They are in same datacenter, using a 1Gb/s connection,
>>>             low latency (0.5ms)
>>>
>>>             I have gluster clients in lan A & B.
>>>
>>>             When doing a "ls" on big folder (~60k files), both
>>>             gluster node are used, and so it need 9mn instead on 1mn
>>>             if only the local gluster is reachable.
>>>
>>
>>             Lookups (and writes of course) from clients are sent to
>>             both  bricks because AFR uses the result of the lookup to
>>             select which brick to read from if there is a pending
>>             heal etc.
>>             If the file is clean on both A and B, then reads are
>>             always served from the local brick. i.e. reads on clients
>>             mounted on A will be served from the brick in A (and
>>             likewise for B).
>>
>>             Hope that helps,
>>             Ravi
>>
>>
>>>             It's HA setup, application is present on both side. I
>>>             would like a master/master setup, but using only local
>>>             node as possible.
>>>
>>>
>>>             Regards,
>>>             Mathieu CHATEAU
>>>             http://www.lotp.fr
>>>
>>>
>>>             _______________________________________________
>>>             Gluster-users mailing list
>>>             Gluster-users at gluster.org  <mailto:Gluster-users at gluster.org>
>>>             http://www.gluster.org/mailman/listinfo/gluster-users
>>
>>
>>
>
>

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