Jon Erdman <postgre...@thewickedtribe.net> writes: > Hi, > > I have SR set up in a couple of datacenters, where there’s a master in > DC_A with 2 slaves, and a 3rd slave off that master in DC_ B. Also, in > DC_B I have 2 slaves chained off the “local master”. Our main database > is ~551GB in DC_A and on the replica in B that is subscribed to the > real master. However, on one of the chained slaves in DC_B that > database is only 484GB. The only thing different about this smaller > slave is that it was created by taking a basebackup from the “local > master” in DC_B rather than sucking it over the WAN from the true > master in DC_A.
Hey Jon. They should be pretty near identical unless there are unlogged tables on master but in such a case all your streamers should be undersized to account for this, not just a single one. I'd troubleshoot by... * Question the size measurement method, df, du etc. * Re-do the streamer and/or build an additional one using same method to see if reproduces. * Determine where the descrepancy is on a per-directory level. I had a system once that had 500G of orphaned heap/index data files after a hard crash that went away finally after a pg_upgrade. If your master and all streamers except that newest one are likewise bloated, this is one possible explanation. Not sure how plausible though. In other words, that extra data was valid, visible and legit at time of creation of all other streamers but now somehow stayed behind after something $interesting happened... and pg_basebackup ignores it. Pls let us know what you find. HTH > This makes no sense to me since I thought SR replicas are bit for bit copies, > so I’m somewhat concerned. Any ideas how this could be? > — > Jon Erdman > Postgres Zealot -- Jerry Sievers Postgres DBA/Development Consulting e: postgres.consult...@comcast.net p: 312.241.7800 -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
