nscd: Improve nscd.conf comments.

Message ID 9f46e84e-72f5-afe1-761a-f47fb47ead5f@redhat.com
State New
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Series
  • nscd: Improve nscd.conf comments.
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Commit Message

Carlos O'Donell March 21, 2019, 2:35 a.m.
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(+)

-- 
2.20.1

Comments

Carlos O'Donell April 9, 2019, 4:28 a.m. | #1
On 3/20/19 10:35 PM, Carlos O'Donell wrote:
> 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.


Ping?

> 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>

>   #



-- 
Cheers,
Carlos.

Patch

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>
  #