[Gluster-users] How to raed / write in geo-replication slave

Sweta Anandpara sanandpa at redhat.com
Wed Jul 15 05:23:51 UTC 2015


Hi Milos,

If I get this correctly, this is your configuration below:

* Geo-rep master- Europe
* Geo-rep slave - Asia
* Same web application installed, and users from Asia are redirected to 
slave (in Asia), users from rest of the world are directed to master (in 
Europe)

And you want read/write facility to be available in slave as well.

YES, this is possible.
BUT, it defeats the purpose of geo-replication. As per the concept of 
disaster recovery, read/writes should be carried out only at the master, 
and slave (if at all used), should be limited to only read workload. In 
your case, the very first write to the slave is going to render your 
geo-rep setup out-of-sync, and you would eventually have to delete off 
all the (new) content at the slave to get back the master and slave in sync.

1. If you are okay with this and would still like to go ahead with 
writes at both master and slave, all you would have to do is get the 
slave volume online.
2. Alternative: IF you are okay with writes happening at only one of the 
place at a time, then you could alternate between making Asia as 
master(and Europe as slave) and Asia as slave (and Europe as master), 
with the steps mentioned in this section of the Admin guide:
http://documentation-devel.engineering.redhat.com/site/documentation/en-US/Red_Hat_Storage/3/html-single/Administration_Guide/index.html#Promoting_a_Slave_to_Master

Would like to reiterate again - (2) is fine..  (1) is NOT recommended.
Do reach out for any other queries.

Thanks,
Shweta




On 07/14/2015 07:57 PM, Milos Cuculovic - MDPI wrote:
> Hi All,
>
> I have two GlusterFS servers, one master and one slave.
> They are doing geo-replication.
>
> I need to read and write on both of them.
>
> Here are some details:
>
> 2 data centers (One in Europe and one in Asia)
> The same web application is installed on both data centers
> Users from Asia are redirected to the Asian DC
> Users from the rest of the World and redirected in Europe
> The application is r/w some files from the glusterFs storage server
> The master is in Europe, and the r/w is fast
> I need people from the Asian DC to also r/w directly in Asia
>
> Is this possible, if so, any help please?
>
> I appriciate your help.
>
> Milos
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> http://www.gluster.org/mailman/listinfo/gluster-users

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