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| Server Tuning |
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| Table of Contents |
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| Max Connections |  |
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| Description: Specifies the maximum concurrent connections that the server can accept.
It includes both plain TCP connections and SSL connections. It should not exceed
the hard limit set by the server: 300 for Standard Edition.
Once this limit is reached, the server will close
Keep-Alive connections when they complete active requests.
|
| Syntax: Integer number |
| Tips: When server is started by root user, the server will try to
adjust the per process file descriptor limits automatically, however,
if it failed, you may need to increase it manually. |
|
| Max SSL Connections | |
|
| Description: Specifies the maximum concurrent SSL connections the server will accept.
Since total concurrent SSL and non-SSL connections will not exceed the limit specified by
Max Connections, the actual number of concurrent SSL connections allowed
could be lower than this limit.
|
| Syntax: Integer number |
|
| Connection Timeout | |
|
| Description: Specifies the maximum allowed connection idle time during processing one request.
The connection will be closed whenever it is idle, no i/o activity, for this period
of time.
|
| Syntax: Integer number |
| Tips: [Security] Set it to as low as you can to help recover dead
connections during potential DoS attack. |
| See Also: |
|
| Max Keep-Alive Requests | |
|
| Description: Specifies the maximum number of requests that can be served through a Keep-Alive (Persistent)
session. Connection will be closed once this limit is reached. You
can set this limit for each virtual host as well.
|
| Syntax: Integer number |
| Tips: [Performance] Set it to a resonable high value. Value <= 1 will disable Keep-Alive. |
| See Also: Virtual Host Max Keep-Alive Requests |
|
| Smart Keep-Alive | |
|
| Description: Specifies whether to turn on Smart Keep-Alive. This option is
effective only if Max Keep-Alive Requests > 1. If enabled,
you can also enable/disable it at virtual host level. Smart keep-alive
will only establish keep-alive connections for requests of JavaScript,
CSS Style Sheet and image files. For html pages, connection will not be kept alive. This
will help serve more users more efficiently. Normally a web page
contains multiple images and scripts that will be cached by the browsers after initial request.
It is more efficient to send those non-html static files through a single keep-alive
connection and have the text/html file send through another non-keep-alive connection. This
method will reduce idle connections and in turn increase capacity to handle more concurrent requests
and users.
|
| Syntax: Select from radio box |
| Tips: [Performance] Enable it for high-load web sites. |
| See Also: Virtual Host Smart Keep-Alive |
|
| Keep-Alive Timeout | |
|
| Description: Specifies the maximum idle time between requests from a Keep-Alive connection.
If no new request is received during this period of time, the connection will be closed.
|
| Syntax: Integer number |
| Tips: [Security & Performance] We recommend you to set the value just long enough to handle
all requests for a single page view. It is unnecessary to keep connection alive
for an extended period of time. A smaller value can reduce idle
connections, increase capacity to service more users and guard against DoS attacks. 2-5 seconds is a
reasonable range for most applications. LiteSpeed is highly efficient in a non-keep-alive environment. |
|
| Send Buffer Size | |
|
| Description: The sending buffer size of each TCP socket. Set to 0 to use the default
buffer size of the operating system. 65535 is the maximum allowed buffer size.
|
| Syntax: Integer number |
| Tips: [Performance] If your web site serves large static files, increase the send buffer
size to improve performance. |
|
| Receive Buffer Size | |
|
| Description: The receiving buffer size of each TCP socket. Set to 0 to use the default
buffer size. 65535 is the hard limit.
|
| Syntax: Integer number |
| Tips: [Performance] A large receive buffer will increase performance when processing
incoming requests with large payload, i.e. file uploads. |
|
| I/O Event Dispatcher | |
|
Description: Specifies which I/O event dispatcher to use. Different
operating systems support different types of event dispatcher:
- Linux kernel 2.4.x supports:
- Linux kernel 2.6.x supports:
- FreeBSD supports:
- Solaris supports:
- Mac OS X 10.3 and above supports:
poll is supported by all platforms, and is the default selection.
For high traffic web sites, altenative event dispatcher can be used to improve the
scalability of the web server.
|
| Syntax: Select from drop down list |
|
| Max Cached Small File Size | |
|
| Description: Specifies the largest static file that will be cached in a
pre-allocated memory buffer. Static files can be served in four different
ways: memory buffer cache, memory-mapped cache, plain read/write and sendfile().
Files whose size is smaller than the Max Cached Small File Size are served
from memory buffer cache. Files whose size is larger than the
Max Cached Small File Size but smaller than the
Max MMAP File Size will be served from memory-mapped cache.
Files whose size is larger than the Max MMAP File Size will be served via
plain read/write or sendfile(). It is optimal to serve static files smaller than 4K from the memory
buffer cache.
|
| Syntax: Integer number |
|
| Total Small File Cache Size | |
|
| Description: Specifies the total memory that can be allocated to
buffer cache in order to cache/serve small static files.
|
| Syntax: Integer number |
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| Max MMAP File Size | |
|
| Description: Specifies the largest static file that will be memory mapped
(MMAP).
Static files can be served in four different
ways: memory buffer cache, memory-mapped cache, plain read/write and sendfile().
Files whose size is smaller than the Max Cached Small File Size are served
from memory buffer cache. Files whose size is larger than the
Max Cached Small File Size but smaller than the
Max MMAP File Size will be served from memory-mapped cache.
Files whose size is larger than the Max MMAP File Size will be served via
plain read/write or sendfile().
Since the server has a 32bit address space, up to 2GB, it is not recommended to mmap
very large files.
|
| Syntax: Integer number |
|
| Total MMAP Cache Size | |
|
| Description: Specifies the total memory that can be allocated for memory
mapped cache in order to cache/serve medium sized static files.
|
| Syntax: Integer number |
|
| Use sendfile() | |
|
| Description: Specifies whether to use sendfile()
system call to serve static files. Static files can be served in four different
ways: memory buffer cache, memory-mapped cache, plain read/write, and sendfile.
File smaller than Max Cached Small File Size is served from memory buffer cache,
file size larger than Max Cached Small File Size but smaller than
Max MMAP File Size will be served from memory-mapped cache.
File larger than Max MMAP File Size will be served via
plain read/write or sendfile. Sendfile() is a "zero copy" system
call that can greatly reduce CPU utilization when serving very large
static files. Sendfile() requires optimized network card kernel driver
and thus may not be applicable for some small-vendor network adapters.
|
| Syntax: Select from radio box |
|
| SSL Hardware Accelerator | |
|
| Description: [Enterprise Edition Only] Specifies which SSL hardware acceleration device to use. Only
devices supported by OpenSSL can be used. Select OpenSSL internal
engine if no device is installed.
|
| Syntax: Select from drop down list |
|
| Max Request URL Length | |
|
| Description: Specifies the maximum size of a request URL. URL is the full text address used to access
a server resource including query string. 8192 bytes is the hard limit.
|
| Syntax: Integer number |
Tips: [Security & Performance] Set it low and reasonable to reduce memory usage
and help identify bogus requests and DoS attacks.
2-3K is big enough for most web
sites unless HTTP GET method is used with large query string instead of POST. |
|
| Max Request Header Size | |
|
| Description: Specifies the maximum size of a HTTP request header including request URL.
Hard limit is 16380 bytes.
|
| Syntax: Integer number |
Tips: [Security & Performance] Set it low and reasonable to reduce memory usage and
help identify bogus requsts and DoS attacks.
4-8K is big enough for most web sites. |
|
| Max Request Body Size | |
|
| Description: Specifies the maximum size of a HTTP request body. 1GB is the hard limit.
|
| Syntax: Integer number |
| Tips: [Security] Set the limit just a little higher than what is really needed to
help identify DoS attack. Your swapping space must have enough free space. |
|
| Max Dynamic Response Header Size | |
|
| Description: Specifies the maximum header size of a dynamically generated response. Hard limit is 8KB
|
| Syntax: Integer number |
| Tips: [Reliability & Performance] Set it low and reasonable to help recognize bad
responses that are dynamically generated by external applications. |
|
| Max Dynamic Response Body Size | |
|
| Description: Specifies the maximum body size of a dynamically generated response. Hard limit is 2047MB.
|
| Syntax: Integer number |
| Tips: [Reliability & Performance] set the limit low and reasonable to help
identify bad responses. For example, it is not uncommon to malformed scripts continaing infinite
loop which leads to infinite sized responses. |
|
| Enable Compression | |
|
| Description: Controls GZIP compression for both static and dynamic HTTP responses.
|
| Syntax: Select from radio box |
| Tips: [Performance] Enable it to save network bandwidth. Text based responses such as
html, css, and javascript files benefit the most and on average can be compressed to 1/2
of original size. |
|
| Enable Dynamic Compression | |
|
| Description: Controls GZIP compression for dynamically generated HTTP response.
Enable Compression must be set to true in order to enable dynamic GZIP compression.
|
| Syntax: Select from radio box |
| Tips: [Performance] Compressing dynamic responses increases CPU and memory
utilization but saves network bandwidth. Text based responses such as
html, css, and javascript files benefit the most and on average can be compressed to 1/2
of original size. |
|
| Compression Level (Dynamic Content) | |
|
| Description: Specifies the level of compression for dynamic contents, ranges
from 1 (lowest) to 9 (highest), default is 2.
|
| Syntax: Number between 1 and 9. |
| Tips: [Performance] Higher compression level will use more memory and CPU cycles.
You can set it to a higher level if your machine has additional power. There is not much difference
between 6 and 9 except 9 uses much more CPU cycles. |
|
| Compressible Types | |
|
| Description: Specifies what MIME types are allowed to be compressed. For example,
if you want to compress text/* but not text/css, you can have a rule like
text/*, !text/css. "!" will exclude that mime type.
|
| Syntax: MIME type list separated by commas. Wild card "*" and
negate sign "!" are allowed, i.e. text/*, !text/js. |
| Tips: [Performance] Only allow types that will benefit from GZIP compression. Binary
files such as gif/png/jpeg images and flash files do not benefit from compression. |
|
| Auto Update Static File | |
|
| Description: Specifies whether to let the web server to create/update GZIP
compressed edition of compressible static files.
If set to Yes, when a file with MIME
type listed in Compressible Types is requested, the web server will
create or update the corresponding compressed file depending on timestamp. The compressed file
is created under the Static GZIP Cache Directory, the file name is based on the MD5
hash of the path of the original file.
|
| Syntax: Select from radio box |
|
| Static GZIP Cache Directory | |
|
| Description: Specifies the path of the directory used to store compressed
file for static content, default is Swapping Directory.
|
| Syntax: Directory Path |
|
| Compression Level (Static Content) | |
|
| Description: Specifies the level of compression for static contents, ranges
from 1 (lowest) to 9 (highest), default is 6.
|
| Syntax: Number between 1 and 9. |
|
| Max Static File Size | |
|
| Description: Specifies the maximum size of a static file for which the
web server will create a compressed file automatically.
|
| Syntax: Number in bytes not less than 1K |
| Tips: [Performance] It is not recommended to have web server create/update
compressed file for large files as the whole server service
would become blocked during that period meaning no further requests can be processed before the
current compression is completed. |
|
| Min Static File Size | |
|
| Description: Specifies the minimum size of a static file for which the
web server will create a corresponding compressed file.
|
| Syntax: Number in bytes not less than 200 |
| Tips: It is not necessary to compress very small files as the bandwidth saving is negligible. |
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Copyright © 2003-2007. Lite Speed Technologies Inc.
All rights reserved. |