Update object-expirer.conf with explanations

Change-Id: Id88eb3b7021beb71e5cd62f7155ae2dc04a68908
Signed-off-by: Prashanth Pai <ppai@redhat.com>

etc/object-expirer.conf-gluster

@@ -1,18 +1,41 @@
-#TODO: Add documentation to explain various options
-#For now, refer: https://github.com/openstack/swift/blob/master/etc/object-expirer.conf-sample
-
 [DEFAULT]
+user = root
 
 [object-expirer]
 user = root
 log_facility = LOG_LOCAL2
-log_level = DEBUG
+log_level = INFO
+
 # The following parameters are used by object-expirer and needs to be same
 # across all conf files!
 auto_create_account_prefix = gs
 expiring_objects_account_name = expiring
 
-interval = 30
+# The swift-object-expirer daemon will run every 'interval' number of seconds
+# interval = 300
+
+# Emit a log line report of the progress so far every 'report_interval'
+# number of seconds.
+# report_interval = 300
+
+# concurrency is the level of concurrency to use to do the work, this value
+# must be set to at least 1
+# concurrency = 1
+
+# processes is how many parts to divide the work into, one part per process
+# that will be doing the work
+# processes set 0 means that a single process will be doing all the work
+# processes can also be specified on the command line and will override the
+# config value
+# processes = 0
+
+# process is which of the parts a particular process will work on
+# process can also be specified on the command line and will overide the config
+# value
+# process is "zero based", if you want to use 3 processes, you should run
+# processes with process set to 0, 1, and 2
+# process = 0
+
 
 [pipeline:main]
 pipeline = catch_errors cache proxy-server