[Pacemaker] PostgreSQL replicarion RA: PGSQL.lock

[Takatoshi MATSUO]

Hi

2013/2/9 Andrew <nitr0 at seti.kr.ua>:
> Hi all.
> For what reason is implemented PGSQL.lock in RA, and what pbs may happen if
> it'll be removed from RA code?

It may cause data inconsistency.
If the file exists in a node, you need to copy data from new master.

> Also, 2nd question: how I can prevent pgsql RA from promoting master before
> both nodes will brings up OR before timeout is reached (for ex., if 2nd node
> is dead)?

You can use xlog_check_count parameter set up with a large number.
RA retries comparing data with specified number of times in Slave.

Or you can use "target-role" such as below too.
----
ms msPostgresql pgsql \
    meta master-max="1" master-node-max="1" clone-max="2"
clone-node-max="1" notify="true" target-role="Slave"
---

> I think that clone of Delay RA for both nodes (to avoid switching
> delay on node with Delay resource failure) will do this - but I can't find
> how I should write such rule, it seems like rules in Pacemaker are too
> simple (or too bad described). I expect something like this (in <> braces I
> included rules that I don't know how to write):
>
> location pgsql_master_location ms_Postgresql \
>     rule $role="master" -inf: <Delay RA is not running> and <ms_Postgresql
> count eq 1>
>
> Is this possible?
>
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