[PATCH] nscd: Improve nscd.conf comments.

[Carlos O'Donell]

This is another patch that attempts to harmonize Fedora with upstream glibc,
and provide some of the same warnings and notes that we have no our nscd.conf
file. I think the note about 'shared' and cache hit rates is particularly
relevant, and we've had users asking us about this for years.

8< --- 8< --- 8<

This change adds a warning to nscd.conf about running multiple caching
services together and that it may lead to unexpected behaviours. Also we
add a note that enabling the 'shared' option will cause cache hit rates
to be misreported (a side effect of the implementation).
---
  ChangeLog      | 4 ++++
  nscd/nscd.conf | 6 ++++++
  2 files changed, 10 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 9765ae0160..a7b90cd1a7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2019-03-20  Carlos O'Donell  <carlos@redhat.com>
+
+	* nscd/nscd.conf: Add warning and comment about shared option.
+
  2019-03-20  Carlos O'Donell  <carlos@redhat.com>
  
  	* nss/nsswitch.conf: Expand comments, and simplify defaults.
diff --git a/nscd/nscd.conf b/nscd/nscd.conf
index 39b875912d..ec8a8c1622 100644
--- a/nscd/nscd.conf
+++ b/nscd/nscd.conf
@@ -3,6 +3,9 @@
  #
  # An example Name Service Cache config file.  This file is needed by nscd.
  #
+# WARNING: Running nscd with a secondary caching service like sssd may lead to
+#          unexpected behaviour, especially with how long entries are cached.
+#
  # Legal entries are:
  #
  #	logfile			<file>
@@ -23,6 +26,9 @@
  #	check-files		<service> <yes|no>
  #	persistent		<service> <yes|no>
  #	shared			<service> <yes|no>
+#	NOTE: Setting 'shared' to a value of 'yes' will accelerate the lookup
+#	      with the help of the client, but these lookups will not be
+#	      counted as cache hits i.e. 'nscd -g' may show '0%'.
  #	max-db-size		<service> <number bytes>
  #	auto-propagate		<service> <yes|no>
  #
-- 
2.20.1