[389-users] changelog deadlock replication failures with DNA

[thierry bordaz]

On 06/18/2013 12:35 AM, Mahadevan, Venkat wrote:
>
>
> I do not know why your environment is prone to trigger db_deadlock 
> (lot of replica agreements, VM, slow disks...).
> I think the best way to progress is that you fill a ticket/bug so that 
> we may track the issue. Note this bug is possibly affecting all 
> operations (ADD/MOD/MODRDN/DEL)
>
> -------
>
> Hi Thierry,
>
> We are running in a VMWare environment, is this known to cause issues 
> and are there any tuning steps you can recommend or things
>
> to watch out for? Thanks and sorry for so many questions.
>
> cheers,
>
> VM
>
Hi Mahadevan,

    Running in a VM should not be an issue if it follows the usual
    tuning recommendation. But of course it adds a layer when
    investigating a RC.
    What is weird is to hit so frequent (50) deadlock in a single DB
    call. In addition it looks like it always happen when updating the
    CL so I can think to only RA threads, CL trimming and Write thread
    (the one holding the backend lock) being in competition. You may try
    to disable the RA for a test to check if they are responsible of
    that. You may also remove the CL maxage to prevent the CL trimming
    thread to be in the loop. Also you may check if you have pb with
    disk IO. Or tune the dbcache to be in memory.
    Sorry I have no easy answer to your question because it requires
    deeper investigations.

best regards
thierry
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