From 44196de2f47d58e990df58e78bb9f2e4b6fe4663 Mon Sep 17 00:00:00 2001 From: Ian Barwick Date: Tue, 3 Mar 2015 16:21:57 +0900 Subject: [PATCH] Add initial FAQ file --- FAQ.md | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 FAQ.md diff --git a/FAQ.md b/FAQ.md new file mode 100644 index 00000000..6d7667aa --- /dev/null +++ b/FAQ.md @@ -0,0 +1,57 @@ +FAQ - Frequently Asked Questions about repmgr +============================================= + + +General +------- + +- What's the difference between the repmgr versions? + + repmgr v3 builds on the improved replication facilities added + in PostgreSQL 9.3, as well as improved automated failover support + via `repmgrd`, and is not compatible with PostgreSQL 9.2 and earlier. + + repmgr v2 supports PostgreSQL 9.0 onwards. While it is compatible + with PostgreSQL 9.3 and later, we recommend repmgr v3. + +- What's the advantage of using replication slots? + + Replication slots, introduced in PostgreSQL 9.4, ensure that the + master server will retain WAL files until they have been consumed + by all standby servers. This makes WAL file management much easier, + and if used `repmgr` will no longer insist on a fixed number (default: 5000) + of WAL files being preserved. + + (However this does mean that if a standby is no longer connected to the + master, the master will retain WAL files indefinitely). + +`repmgr` +-------- + +- When should I use the --rsync-only option? + + By default, `repmgr` uses `pg_basebackup` to clone a standby from + a master. However, `pg_basebackup` copies the entire data directory, which + can take some time depending on installation size. If you have an + existing but "stale" standby, `repmgr` can use `rsync` instead, + which means only changed or added files need to be copied. + +- Can I register an existing master/standby? + + Yes, this is no problem. + +- Is there an easy way to check my master server is correctly configured + for use with `repmgr`? + + Yes - execute `repmgr` with the `--check-upstream-config` option, and it + will let you know which items in `postgresql.conf` need to be modified. + +`repmgrd` +--------- + +- Do I need a witness server? + + Not necessarily. However if you have an uneven number of nodes spread + over more than one network segment, a witness server will enable + better handling of a 'split brain' situation by providing a "casting + vote" on the preferred network segment. \ No newline at end of file