config_advanced.txt

Revision 2466, 4.9 kB (checked in by taher, 1 week ago)
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1	== link:index.html[Index] -> link:config.html[Configuration]
2
3	Advanced Configuration
4	----------------------
5
6	Through this section you can fine-tune several of Cherokee's
7	parameters. You should not attempt to do so unless you really know
8	what you are doing. For most cases the default parameters will work
9	just fine.
10
11	image::media/images/admin_advanced0.png[Cherokee Admin interface]
12
13	You should at least read the chapter
14	link:cookbook_optimizations.html[Optimizing Cherokee] before you
15	start tweaking things here.
16
17	[[connections]]
18	Connections
19	~~~~~~~~~~~
20	* KeepAlive:
21	Enables the global keep-alive support for the client requests. It
22	increases the client performance by reusing a connection for more
23	than one request. It should most probably be turned on.
24
25	* Max keepalive reqs:
26	This limits the number of HTTP requests that can be served by each
27	keepalive connection. Keepalive connections improve performance, but
28	surpasing certain amount of requests per each connection is an
29	indicator that something out of the ordinary is happening. This
30	prevents the appearence of any problems related to these situations.
31
32	* Chunked encoding:
33	Enabled by default to try to keep enabled Keep-Alive.
34
35	* Polling Method: This affects the internal file descriptor polling
36	method among the ones supported by the OS. The full list of options
37	is `epoll()`, `kqueue`, `poll()`, `Solaris ports`, `select()` and
38	`Win32`. Only the alternatives available for your specific
39	architectures are shown. If you don't know what this is or how this
40	affects performance, just choose `Automatic`. This will choose the
41	most efficient one among the present at any given time.
42
43	* Sendfile min/max size:
44	These allow to configure the range of file sizes that can be sent
45	with `sendfile()`. Default: [32768 Bytes - 2 GB].
46
47	image::media/images/admin_advanced1.png[Cherokee Admin interface]
48
49	[[resources]]
50	Resources
51	~~~~~~~~~
52	* Thread Number:
53	Adjust the number of threads for Cherokee to work with. Increasing
54	this will allow for better parallelization at the cost of system
55	resources. Highly constrained environments such as embedded devices
56	will probably be fine with just one. This doesn't translate into
57	just one connection at the time, since a thread can handle many.
58
59	* Thread Policy:
60	Defines the thread policy to be applied by the OS: FIFO, Round Robin
61	or Dynamic.
62
63	* File descriptors:
64	This can alter the number of file descriptors handled by the server
65	should handle. The default value is what `ulimit -n` reports. An
66	increase in this value improves performance under very high server load.
67
68	* Listening queue length: This specifies the size of the incoming
69	connection queue. It is the effective buffer of connections that
70	will be served even if there are no connection slots available at
71	the moment.
72
73	* Reuse connections:
74	Cherokee implements an intelligent mechanism to reuse connections if
75	possible, allowing it to improve performance by not having to
76	reinitialize structures in memory that can serve perfectly well for
77	more than one time. It defaults to 20. Though this mechanism is an obvious
78	improvent, reducing this limit is useful for cases when a sudden
79	burst of connections happens. In those cases it doesn't make much
80	sense to keep reusing many more connections than those of an average
81	load for any other moment.
82
83	* Log flush time:
84	Time interval in seconds to wait between log updates. Defaults to 10
85	seconds.
86
87	* Nonces clean up time:
88	Time interval in seconds between Nonce cache clean ups. Defaults to
89	60 seconds.
90
91	image::media/images/admin_advanced2.png[Cherokee Admin interface]
92
93	[[io_cache]]
94	I/O cache
95	~~~~~~~~~
96	* Status:
97	Enabled by default. This is a system-wide setting required if you
98	wish to enable caching in any of your virtual hosts. Useful for debugging.
99
100	* Max pages:
101	This specifies the maximum number of pages that are handled by the cache.
102
103	* File Min Size:
104	Specifies the smallest filesize limit to be cached.
105
106	* File Max Size:
107	Specifies the biggest filesize limit to be cached.
108
109	* Lasting _stat_:
110	Specifies the duration of the file information in the cache without
111	refreshing.
112
113	* Lasting _mmap_:
114	Specifies how long the file contents last cached.
115
116	image::media/images/admin_advanced3.png[Cherokee Admin interface]
117
118	[[special_files]]
119	Special Files
120	~~~~~~~~~~~~~
121	* Panic action:
122	This specifies the program that will be called in case the server
123	fails. It defaults to `cherokee-panic`, which is provided with
124	Cherokee. This in turn performs the actions specified in the
125	`CHEROKEE_PANIC_OUTPUT` environment variable. If none is set, it will
126	attempt to send an email to the system administrator with a
127	backtrace of what happened. As a last resort, if no mailer is
128	available in the system, it will simply try to show this information
129	on screen if possible.
130
131	* PID file:
132	If specified, a PID file will be created in that path. This is
133	useful to trace what is going on with Cherokee.
134
135	image::media/images/admin_advanced4.png[Cherokee Admin interface]

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