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<modulesynopsis metafile="mod_disk_cache.xml.meta">

<name>mod_disk_cache</name>

<description>Content cache storage manager keyed to URIs</description>

<status>Experimental</status>

<sourcefile>mod_disk_cache.c</sourcefile>

<identifier>disk_cache_module</identifier>

<summary>

<note type="warning">

This module is experimental. Documentation is still under development...

</note>

<p><module>mod_disk_cache</module> implements a disk based storage

manager. It is primarily of use in conjunction with

<module>mod_proxy</module>.</p>

<p>Content is stored in and retrieved from the cache using URI based

keys. Content with access protection is not cached.</p>

<note><title>Note:</title>

<p><module>mod_disk_cache</module> requires the services of

<module>mod_cache</module>.</p>

</note>

</summary>

<directivesynopsis>

<name>CacheRoot</name>

<description>The directory root under which cache files are

stored</description>

<syntax>CacheRoot <var>directory</var></syntax>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>The <directive>CacheRoot</directive> directive defines the name of

the directory on the disk to contain cache files. If the <module

>mod_disk_cache</module> module has been loaded or compiled in to the

Apache server, this directive <em>must</em> be defined. Failing to

provide a value for <directive>CacheRoot</directive> will result in

a configuration file processing error. The <directive

module="mod_disk_cache">CacheDirLevels</directive> and <directive

module="mod_disk_cache">CacheDirLength</directive> directives define

the structure of the directories under the specified root directory.</p>

<example>

CacheRoot c:/cacheroot

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheSize</name>

<description>The maximum amount of disk space that will be used by the

cache in KBytes</description>

<syntax>CacheSize <var>KBytes</var></syntax>

<default>CacheSize 1000000</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>The <directive>CacheSize</directive> directive sets the desired

disk space usage of the cache, in KBytes (1024-byte units). This

directive does not put a hard limit on the size of the cache. The

garbage collector will delete files until the usage is at or below the

settings. Always use a value that is lower than the available disk

space.</p>

<example>

CacheSize 5000000

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheGcInterval</name>

<description>The interval between garbage collection attempts.</description>

<syntax>CacheGcInterval <var>hours</var></syntax>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>The <directive>CacheGcInterval</directive> directive specifies the

number of hours to wait between attempts to free up disk space.</p>

<p>More detail will be added here, when the function is implemented.</p>

<example>

CacheGcInterval 24<br />

</example>

<note type="warning">

The <directive>CacheGcInterval</directive> directive is currently

<em>not</em> implemented.

</note>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheDirLevels</name>

<description>The number of levels of subdirectories in the

cache.</description>

<syntax>CacheDirLevels <var>levels</var></syntax>

<default>CacheDirLevels 3</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>The <directive>CacheDirLevels</directive> directive sets the number

of subdirectory levels in the cache. Cached data will be saved this

many directory levels below the <directive module="mod_disk_cache"

>CacheRoot</directive> directory.</p>

<note>

<p>The result of <directive>CacheDirLevels</directive>*

<directive module="mod_disk_cache">CacheDirLength</directive> must

not be higher than 20.</p>

</note>

<example>

CacheDirLevels 5

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheDirLength</name>

<description>The number of characters in subdirectory names</description>

<syntax>CacheDirLength <var>length</var></syntax>

<default>CacheDirLength 2</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>The <directive>CacheDirLength</directive> directive sets the number

of characters for each subdirectory name in the cache hierarchy.</p>

<note>

<p>The result of <directive module="mod_disk_cache"

>CacheDirLevels</directive>* <directive>CacheDirLength</directive>

must not be higher than 20.</p>

</note>

<example>

CacheDirLength 4

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheExpiryCheck</name>

<description>Indicates if the cache observes Expires dates when seeking

files</description>

<syntax>CacheExpiryCheck On|Off</syntax>

<default>CacheExpiryCheck On</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>More detail will be added here, when the function is implemented.</p>

<example>

CacheExpiryCheck Off<br />

</example>

<note type="warning">

The <directive>CacheExpiryCheck</directive> directive is currently

<em>not</em> implemented.

</note>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheMinFileSize</name>

<description>The minimum size (in bytes) of a document to be placed in the

cache</description>

<syntax>CacheMinFileSize <var>bytes</var></syntax>

<default>CacheMinFileSize 1</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>The <directive>CacheMinFileSize</directive> directive sets the

minimum size, in bytes, for a document to be considered for storage

in the cache.</p>

<example>

CacheMinFileSize 64

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheMaxFileSize</name>

<description>The maximum size (in bytes) of a document to be placed in the

cache</description>

<syntax>CacheMaxFileSize <var>bytes</var></syntax>

<default>CacheMaxFileSize 1000000</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>The <directive>CacheMaxFileSize</directive> directive sets the

maximum size, in bytes, for a document to be considered for storage in

the cache.</p>

<example>

CacheMaxFileSize 64000

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheTimeMargin</name>

<description>The minimum time margin to cache a document</description>

<syntax>CacheTimeMargin <var>?</var></syntax>

<default>CacheTimeMargin ?</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>More detail will be added here, when the function is implemented.</p>

<example>

CacheTimeMargin X

</example>

<note type="warning">

The <directive>CacheTimeMargin</directive> directive is currently

<em>not</em> implemented.

</note>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheGcDaily</name>

<description>The recurring time each day for garbage collection to be run.

(24 hour clock)</description>

<syntax>CacheGcDaily <var>time</var></syntax>

<default>CacheGcDaily ?</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>More detail will be added here, when the function is implemented.</p>

<example>

CacheGcDaily 23:59

</example>

<note type="warning">

The <directive>CacheGcDaily</directive> directive is currently

<em>not</em> implemented.

</note>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheGcUnused</name>

<description>The time to retain unreferenced cached files that match a

URL.</description>

<syntax>CacheGcUnused <var>hours</var> <var>url-string</var></syntax>

<default>CacheGcUnused ?</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>More detail will be added here, when the function is implemented.</p>

<example>

CacheGcUnused 12 /local_images

</example>

<note type="warning">

The <directive>CacheGcUnused</directive> directive is currently

<em>not</em> implemented.

</note>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheGcClean</name>

<description>The time to retain unchanged cached files that match a

URL</description>

<syntax>CacheGcClean <var>hours</var> <var>url-string</var></syntax>

<default>CacheGcClean ?</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>More detail will be added here, when the function is implemented.</p>

<example>

CacheGcClean 12 /daily_scripts

</example>

<note type="warning">

The <directive>CacheGcClean</directive> directive is currently

<em>not</em> implemented.

</note>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheGcMemUsage</name>

<description>The maximum kilobytes of memory used for garbage

collection</description>

<syntax>CacheGcMemUsage <var>KBytes</var></syntax>

<default>CacheGcMemUsage ?</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<usage>

<p>More detail will be added here, when the function is implemented.</p>

<example>

CacheGcMemUsage 16

</example>

<note type="warning">

The <directive>CacheGcMemUsage</directive> directive is currently

<em>not</em> implemented.

</note>

</usage>

</directivesynopsis>

</modulesynopsis>