Apache Module mod_cache_socache

Available Languages: en

+ + + +

Description:	Shared object cache (socache) based storage module for the +HTTP caching filter.
Status:	Extension
Module Identifier:	cache_socache_module
Source File:	mod_cache_socache.c

Summary

+ +

mod_cache_socache implements a shared object cache + (socache) based storage manager for mod_cache.

+ +

The headers and bodies of cached responses are combined, and stored + underneath a single key in the shared object cache. A + number of implementations of shared object + caches are available to choose from.

+ +

Multiple content negotiated responses can be stored concurrently, + however the caching of partial content is not yet supported by this + module.

+ +

+# Turn on caching
+CacheSocache shmcb
+CacheSocacheMaxSize 102400
+<Location /foo>
+    CacheEnable socache
+</Location>
+
+# Fall back to the disk cache
+CacheSocache shmcb
+CacheSocacheMaxSize 102400
+<Location /foo>
+    CacheEnable socache
+    CacheEnable disk
+</Location>
+

+ + +

Note:

mod_cache_socache requires the services of + mod_cache, which must be loaded before + mod_cache_socache.

CacheSocache Directive

+ + + + + + + +

Description:	The directory root under which cache files are +stored
Syntax:	`CacheSocache type[:args]`
Context:	server config, virtual host
Status:	Extension
Module:	mod_cache_socache
Compatibility:	Available in Apache 2.5 and later

The CacheSocache directive defines the name of + the shared object cache implementation to use, followed by optional + arguments for that implementation. A number of + implementations of shared object caches are available to choose + from.

+ +

+      CacheSocache shmcb
+

+ + +

CacheSocacheMaxSize Directive

+ + + + + + + + +

Description:	The maximum size (in bytes) of an entry to be placed in the +cache
Syntax:	`CacheSocacheMaxSize bytes`
Default:	`CacheSocacheMaxSize 102400`
Context:	server config, virtual host, directory, .htaccess
Status:	Extension
Module:	mod_cache_socache
Compatibility:	Available in Apache 2.5 and later

The CacheSocacheMaxSize directive sets the + maximum size, in bytes, for the combined headers and body of a document + to be considered for storage in the cache. The larger the headers that + are stored alongside the body, the smaller the body may be.

+ +

The mod_cache_socache module will only attempt to + cache responses that have an explicit content length, or that are small + enough to be written in one pass. This is done to allow the + mod_cache_disk module to have an opportunity to cache + responses larger than those cacheable within + mod_cache_socache.

+ +

+      CacheSocacheMaxSize 102400
+

+ + +

CacheSocacheMaxTime Directive

+ + + + + + + + +

Description:	The maximum time (in seconds) for a document to be placed in the +cache
Syntax:	`CacheSocacheMaxTime seconds`
Default:	`CacheSocacheMaxTime 86400`
Context:	server config, virtual host, directory, .htaccess
Status:	Extension
Module:	mod_cache_socache
Compatibility:	Available in Apache 2.5 and later

The CacheSocacheMaxTime directive sets the + maximum freshness lifetime, in seconds, for a document to be stored in + the cache. This value overrides the freshness lifetime defined for the + document by the HTTP protocol.

+ +

+      CacheSocacheMaxTime 86400
+

+ + +

CacheSocacheMinTime Directive

+ + + + + + + + +

Description:	The maximum time (in seconds) for a document to be placed in the +cache
Syntax:	`CacheSocacheMinTime seconds`
Default:	`CacheSocacheMinTime 600`
Context:	server config, virtual host, directory, .htaccess
Status:	Extension
Module:	mod_cache_socache
Compatibility:	Available in Apache 2.5 and later

The CacheSocacheMinTime directive sets the + amount of seconds beyond the freshness lifetime of the response that the + response should be cached for in the shared object cache. If a response is + only stored for its freshness lifetime, there will be no opportunity to + revalidate the response to make it fresh again.

+ +

+      CacheSocacheMinTime 600
+

+ + +

CacheSocacheReadSize Directive

+ + + + + + + + +

Description:	The minimum size (in bytes) of the document to read and be cached + before sending the data downstream
Syntax:	`CacheSocacheReadSize bytes`
Default:	`CacheSocacheReadSize 0`
Context:	server config, virtual host, directory, .htaccess
Status:	Extension
Module:	mod_cache_socache
Compatibility:	Available in Apache 2.5 and later

The CacheSocacheReadSize directive sets the + minimum amount of data, in bytes, to be read from the backend before the + data is sent to the client. The default of zero causes all data read of + any size to be passed downstream to the client immediately as it arrives. + Setting this to a higher value causes the disk cache to buffer at least + this amount before sending the result to the client. This can improve + performance when caching content from a slow reverse proxy.

+ +

This directive only takes effect when the data is being saved to the + cache, as opposed to data being served from the cache.

+ +

+      CacheReadSize 102400
+

+ + +

CacheSocacheReadTime Directive

+ + + + + + + + +

Description:	The minimum time (in milliseconds) that should elapse while reading + before data is sent downstream
Syntax:	`CacheSocacheReadTime milliseconds`
Default:	`CacheSocacheReadTime 0`
Context:	server config, virtual host, directory, .htaccess
Status:	Extension
Module:	mod_cache_socache
Compatibility:	Available in Apache 2.5 and later

The CacheSocacheReadTime directive sets the minimum amount + of elapsed time that should pass before making an attempt to send data + downstream to the client. During the time period, data will be buffered + before sending the result to the client. This can improve performance when + caching content from a reverse proxy.

+ +

The default of zero disables this option.

+ +

This directive only takes effect when the data is being saved to the + cache, as opposed to data being served from the cache. It is recommended + that this option be used alongside the + CacheSocacheReadSize directive + to ensure that the server does not buffer excessively should data arrive faster + than expected.

+ +

+      CacheSocacheReadTime 1000
+

+ + +

Comments

Notice:
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BalancerInherit Directive

Description:	Inherit ProxyPassed Balancers/Workers from the main server
Syntax:	`BalancerInherit On\|Off`
Default:	`BalancerInherit On`
Context:	server config, virtual host
Status:	Extension
Module:	mod_proxy
Compatibility:	BalancerInherit is only available in Apache HTTP Server 2.5.0 + and later.

Description:

Inherit ProxyPassed Balancers/Workers from the main server

Syntax:

BalancerInherit On|Off

Default:

BalancerInherit On

Context:

server config, virtual host

Status:

Extension

Module:

mod_proxy

Compatibility:

BalancerInherit is only available in Apache HTTP Server 2.5.0 + and later.

This directive will cause the current server/vhost to "inherit" ProxyPass + Balancers and Workers defined in the main server. This can cause issues and + inconsistent behavior if using the Balancer Manager and so should be disabled + if using that feature.

The setting in the global server defines the default for all vhosts.

ProxyPassInherit Directive

Description:	Inherit ProxyPass directives defined from the main server
Syntax:	`ProxyPassInherit On\|Off`
Default:	`ProxyPassInherit On`
Context:	server config, virtual host
Status:	Extension
Module:	mod_proxy
Compatibility:	ProxyPassInherit is only available in Apache HTTP Server 2.5.0 and later. + and later.

Description:

Inherit ProxyPass directives defined from the main server

Syntax:

ProxyPassInherit On|Off

Default:

ProxyPassInherit On

Context:

server config, virtual host

Status:

Extension

Module:

mod_proxy

Compatibility:

ProxyPassInherit is only available in Apache HTTP Server 2.5.0 and later. + and later.

This directive will cause the current server/vhost to "inherit" + ProxyPass + directives defined in the main server. This can cause issues and + inconsistent behavior if using the Balancer Manager for dynamic changes + and so should be disabled if using that feature.

The setting in the global server defines the default for all vhosts.

Disabling ProxyPassInherit also disables BalancerInherit.

Apache Module mod_cache_socache

Summary

Note:

Directives

See also

CacheSocache Directive

CacheSocacheMaxSize Directive

CacheSocacheMaxTime Directive

CacheSocacheMinTime Directive

CacheSocacheReadSize Directive

CacheSocacheReadTime Directive

Comments

Directives

BalancerInherit Directive

BalancerMember Directive

ProxyPassInherit Directive

ProxyPassInterpolateEnv Directive