Marian,

a few more comments:

> mysql_notify() {
>     if [ "$OCF_RESKEY_CRM_meta_notify_type" != 'post' ]; then
>         return $OCF_SUCCESS
>     fi
>     case "$OCF_RESKEY_CRM_meta_notify_operation" in
>         'promote')
>             if [ "$OCF_RESKEY_CRM_meta_notify_promote_uname" != "$HOSTNAME " 
> ] &&
>                 ! is_slave 1; then
>                 mysql_demote 1
>             fi
>         ;;

Now wait a minute. You are being _notified_ that some other node just
got promoted. You can't demote yourself here now. It's Pacemaker's job
to decide that.

>         'demote')
>             if [ "$OCF_RESKEY_CRM_meta_notify_promote_uname" = "$HOSTNAME " ] 
> &&
>                 ! is_slave 1; then
>                 mysql_demote 1
>             fi

Same thing here. You are just being _told_ that a demotion just
happened. That's no reason for demoting yourself.

Sorry for quoting myself here; I wrote this about promote/demote/notify
a few days ago and have yet to be corrected -- I wouldn't mind at all
being corrected, though. :)

> What you want to do, IMHO, is this:
> 
> * promote operation:
>   - Unset read-only mode.
>   - Pacemaker will take care of notifying the slaves of the new master
> 
> * demote operation:
>   - essentially a no-op. During demote, you may not have a clue which
> box is the new master, in fact there may not be one in the cluster at
> all if the admin just typed in "crm resource demote <your_ms_resource>.
> So there's no point in reconfiguring a master as a slave during a
> demote. The only thing you may want to to is set it to read-only mode.
> 
> * notify operation:
>   - post-promote: you've just been informed of the new master. STOP SLAVE,
> SET MASTER TO, START SLAVE.
>   - post-demote: you've just been informed that there currently is no
> master. STOP SLAVE. Keep running in read-only mode.
> 
> * start operation:
>   - Just like in a standalone MySQL resource, except that you set
> read-only mode.

Thoughts?

Cheers,
Florian

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