[Gluster-devel] Server-side AFR + Failover and mixed server/client-side AFR

[gordan at bobich.net]

On Wed, 7 May 2008, Krishna Srinivas wrote:

>>>> >  Is this an issue in server-side-only AFR? I have two servers which
>>>> > are also clients of themselves, and they both list their local 
>>>> > subvolume first and
>>>> > remote subvolume second. Is this a problem? What are the possible
>>>> > consequences of this?
>>>>
>>>>  It will be a problem. The "first" subvol is always the "lock" server.
>>>>  Consider a case where you are creating a file simultaneously
>>>>  on two clients, only one of them should succeed. If AFR's
>>>>  subvols order are not same, chances are that both client
>>>>  returns success for file creation with same name.
>>>>
>>>
>>> Hence you have "option read-subvlume" to speeden the
>>> read() calls so that it can be done from local subvol.
>>>
>>
>>  So, what happens if the "lock" server is the one that goes down?  Will that
>> render the whole AFR cluster inoperable, at least for writes?
>>
>
> If first server is down, the second one is tried and so on. The cluster remains
> operable.

Does the lock state remain for the locks when the primary/lock server 
dies? If so, how?

Gordan