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comparison xml/en/docs/http/ngx_http_upstream_module.xml @ 1230:6cc809881694

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Upstream: added the "hash" directive.
author Yaroslav Zhuravlev <yar@nginx.com>
date Tue, 17 Jun 2014 17:05:37 +0400
parents 9264fdb6c833
children ab2ea38f3512
comparison
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1229:7dd620e507c3 1230:6cc809881694
8 <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd"> 8 <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd">
9 9
10 <module name="Module ngx_http_upstream_module" 10 <module name="Module ngx_http_upstream_module"
11 link="/en/docs/http/ngx_http_upstream_module.html" 11 link="/en/docs/http/ngx_http_upstream_module.html"
12 lang="en" 12 lang="en"
13 rev="23"> 13 rev="24">
14 14
15 <section id="summary"> 15 <section id="summary">
16 16
17 <para> 17 <para>
18 The <literal>ngx_http_upstream_module</literal> module 18 The <literal>ngx_http_upstream_module</literal> module
296 </para> 296 </para>
297 297
298 </directive> 298 </directive>
299 299
300 300
301 <directive name="hash">
302 <syntax><value>key</value> [<literal>consistent</literal>]</syntax>
303 <default/>
304 <context>upstream</context>
305 <appeared-in>1.7.2</appeared-in>
306
307 <para>
308 Specifies a load balancing method for a server group
309 where client-server mapping is based on the hashed <value>key</value> value.
310 The <value>key</value> can contain text, variables, and their combinations.
311 Note that adding or removing a server from the group
312 may result in remapping most of the keys to different servers.
313 The method is compatible with the
314 <link url="http://search.cpan.org/perldoc?Cache%3A%3AMemcached">Cache::Memcached</link>
315 Perl library.
316 </para>
317
318 <para>
319 The <literal>consistent</literal> parameter specifies that
320 the <link url="http://www.last.fm/user/RJ/journal/2007/04/10/392555/">ketama</link>
321 consistent hashing method should be used instead.
322 The method ensures that only a few keys
323 will be remapped to different servers
324 when a server is added to or removed from the group.
325 This helps to achieve a higher cache hit ratio for caching servers.
326 The method is compatible with the
327 <link url="http://search.cpan.org/perldoc?Cache%3A%3AMemcached%3A%3AFast">Cache::Memcached::Fast</link>
328 Perl library with the <value>ketama_points</value> parameter is set to 160.
329 </para>
330
331 </directive>
332
333
301 <directive name="ip_hash"> 334 <directive name="ip_hash">
302 <syntax/> 335 <syntax/>
303 <default/> 336 <default/>
304 <context>upstream</context> 337 <context>upstream</context>
305 338