On 06.10.2010 11:09, Fujii Masao wrote:
> On Wed, Oct 6, 2010 at 3:31 PM, Heikki Linnakangas
> <heikki.linnakangas@enterprisedb.com> wrote:
>> No. Synchronous replication does not help with availability. It allows you
>> to achieve zero data loss, ie. if the master dies, you are guaranteed that
>> any transaction that was acknowledged as committed, is still committed.
>
> Hmm.. but we can increase availability without any data loss by using
> synchronous
> replication. Many people have already been using synchronous
> replication softwares
> such as DRBD for that purpose.
Sure, but it's not the synchronous aspect that increases availability.
It's the replication aspect, and we already have that. Making the
replication synchronous allows zero data loss in case the master
suddenly dies, but it comes at the cost of availability.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com