nscd.conf — name service cache daemon configuration file


The file /etc/nscd.conf is read from nscd(8) at startup. Each line specifies either an attribute and a value, or an attribute, service, and a value. Fields are separated either by SPACE or TAB characters. A '#' (number sign) indicates the beginning of a comment; following characters, up to the end of the line, are not interpreted by nscd.

Valid services are passwd, group, hosts, services, or netgroup.

logfile debug-file-name

Specifies name of the file to which debug info should be written.

debug-level value

Sets the desired debug level. The default is 0.

threads number

This is the number of threads that are started to wait for requests. At least five threads will always be created.

max-threads number

Specifies the maximum number of threads. The default is 32.

server-user user

If this option is set, nscd will run as this user and not as root. If a separate cache for every user is used (−S parameter), this option is ignored.

stat-user user

Specifies the user who is allowed to request statistics.

reload-count unlimited | number

Limit on the number of times a cached entry gets reloaded without being used before it gets removed. The default is 5.

paranoia <yes|no>

Enabling paranoia mode causes nscd to restart itself periodically. The default is no.

restart-interval time

Sets the restart interval to time seconds if periodic restart is enabled by enabling paranoia mode. The default is 3600.

enable-cache service <yes|no>

Enables or disables the specified service cache. The default is no.

positive-time-to-live service value

Sets the TTL (time-to-live) for positive entries (successful queries) in the specified cache for service. Value is in seconds. Larger values increase cache hit rates and reduce mean response times, but increase problems with cache coherence.

negative-time-to-live service value

Sets the TTL (time-to-live) for negative entries (unsuccessful queries) in the specified cache for service. Value is in seconds. Can result in significant performance improvements if there are several files owned by UIDs (user IDs) not in system databases (for example untarring the Linux kernel sources as root); should be kept small to reduce cache coherency problems.

suggested-size service value

This is the internal hash table size, value should remain a prime number for optimum efficiency. The default is 211.

check-files service <yes|no>

Enables or disables checking the file belonging to the specified service for changes. The files are /etc/passwd, /etc/group, /etc/hosts, /etc/services and /etc/netgroup. The default is yes.

persistent service <yes|no>

Keep the content of the cache for service over server restarts; useful when paranoia mode is set. The default is no.

shared service <yes|no>

The memory mapping of the nscd databases for service is shared with the clients so that they can directly search in them instead of having to ask the daemon over the socket each time a lookup is performed. The default is no.

max-db-size service bytes

The maximum allowable size, in bytes, of the database files for the service. The default is 33554432.

auto-propagate service <yes|no>

When set to no for passwd or group service, then the .byname requests are not added to passwd.byuid or group.bygid cache. This can help with tables containing multiple records for the same ID. The default is yes. This option is valid only for services passwd and group.


The default values stated in this manual page originate from the source code of nscd(8) and are used if not overridden in the configuration file. The default values used in the configuration file of your distribution might differ.




This page is part of release 4.07 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at−pages/.

  Copyright (c) 1999, 2000 SuSE GmbH Nuernberg, Germany
Author: Thorsten Kukuk <>

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