On Thu, Mar 3, 2011 at 6:33 AM, Robert Haas <robertmh...@gmail.com> wrote: > I don't understand how synchronous replication with > allow_standalone_primary=on gives you ANY extra nines.
When you start the primary (or when there is one connected standby and it crashes), allow_standalone_primary = on allows the database service to proceed. OTOH, setting the parameter to off keeps the service stopping until new standby has connected and has caught up with the primary. This would cause long service down time, and decrease the availability. Of course, running the primary alone has the risk. If its disk gets corrupted before new standby appears, some committed transactions are lost. But we can decrease this risk to a certain extent by using RAID or something to the storage. So I think that some systems can accept the risk and prefer the availability of the database service. Josh explained clearly before why allow_standalone_primary = off is required for his case. http://archives.postgresql.org/message-id/4CAE2488.9020207%40agliodbs.com Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
