From be90ab01bb46ed38ab6c2dd737c66a9537c04327 Mon Sep 17 00:00:00 2001 From: Martin Schwenke Date: Tue, 18 Feb 2020 18:32:21 +1100 Subject: [PATCH] ctdb-docs: Improve recovery lock documentation Signed-off-by: Martin Schwenke Reviewed-by: Christof Schmitt Autobuild-User(master): Martin Schwenke Autobuild-Date(master): Mon Mar 9 02:27:18 UTC 2020 on sn-devel-184 --- ctdb/doc/ctdb.7.xml | 33 +++++++++++++++++++++++++++------ 1 file changed, 27 insertions(+), 6 deletions(-) diff --git a/ctdb/doc/ctdb.7.xml b/ctdb/doc/ctdb.7.xml index 09fb4ed7d8f..2079ed713e3 100644 --- a/ctdb/doc/ctdb.7.xml +++ b/ctdb/doc/ctdb.7.xml @@ -112,12 +112,33 @@ The recovery lock can also be implemented using an arbitrary - cluster mutex call-out by using an exclamation point ('!') as - the first character of recovery lock. - For example, a value of !/usr/local/bin/myhelper - recovery would run the given helper with the specified - arguments. See the source code relating to cluster mutexes for - clues about writing call-outs. + cluster mutex helper (or call-out). This is indicated by using + an exclamation point ('!') as the first character of the + recovery lock parameter. For example, a + value of !/usr/local/bin/myhelper recovery + would run the given helper with the specified arguments. The + helper will continue to run as long as it holds its mutex. See + ctdb/doc/cluster_mutex_helper.txt in the + source tree, and related code, for clues about writing helpers. + + + + When a file is specified for the recovery + lock parameter (i.e. no leading '!') the file lock + is implemented by a default helper + (/usr/local/libexec/ctdb/ctdb_mutex_fcntl_helper). + This helper has arguments as follows: + + + +ctdb_mutex_fcntl_helper FILE RECHECK-INTERVAL + + + ctdb_mutex_fcntl_helper will take a lock on + FILE and then check every RECHECK-INTERVAL seconds to ensure + that FILE still exists and that its inode number is unchanged + from when the lock was taken. The default value for + RECHECK-INTERVAL is 5. -- 2.11.4.GIT