Linux Performance Tuning

When a distribution is packaged and delivered to clients, it is designed to be fully compatible with most of the computers available in the market. This is a very heterogeneous set of hardware (hard disks, video cards, network cards, etc.). So distribution vendors like Red Hat, SuSe, Mandriva and the rest of them choose some conservative configuration options to assure a successful installation.

http://www.linuxforums.org/desktop/linux_performance_tuning.html

Lm Sensors

http://secure.netroedge.com/~lm78/supported.html

Dilbert

Theodore Ts'o

One of the core kernel developers for the Linux operating system. Implemented and maintained the serial driver, POSIX job control, POSIX signal handling, and the ext2 filesystem utilities. Chair of the Technical Board for Linux International. Developed a device driver for the Rocketport intelligent serial board on contract for Comtrol, Inc. Maintainer of the TSX-11.MIT.EDU ftp site (first ftp in U.S.A. to house Linux).

Squid Result Codes

TCP_HIT
A valid copy of the requested object was in the cache.

TCP_MISS
The requested object was not in the cache.

TCP_REFRESH_HIT
The requested object was cached but STALE. The IMS query for the object resulted in "304 not modified".

TCP_REF_FAIL_HIT
The requested object was cached but STALE. The IMS query failed and the stale object was delivered.

TCP_REFRESH_MISS
The requested object was cached but STALE. The IMS query returned the new content.

TCP_CLIENT_REFRESH_MISS
The client issued a "no-cache" pragma, or some analogous cache control command along with the request. Thus, the cache has to refetch the object.

TCP_IMS_HIT
The client issued an IMS request for an object which was in the cache and fresh.

TCP_SWAPFAIL_MISS
The object was believed to be in the cache, but could not be accessed.

TCP_NEGATIVE_HIT
Request for a negatively cached object, e.g. "404 not found", for which the cache believes to know that it is inaccessible. Also refer to the explainations for negative_ttl in your squid.conf file.

TCP_MEM_HIT
A valid copy of the requested object was in the cache and it was in memory, thus avoiding disk accesses.

TCP_DENIED
Access was denied for this request.

TCP_OFFLINE_HIT
The requested object was retrieved from the cache during offline mode. The offline mode never validates any object, see offline_mode in squid.conf file.

UDP_HIT
A valid copy of the requested object was in the cache.

UDP_MISS
The requested object is not in this cache.

UDP_DENIED
Access was denied for this request.

UDP_INVALID
An invalid request was received.

UDP_MISS_NOFETCH
During "-Y" startup, or during frequent failures, a cache in hit only mode will return either UDP_HIT or this code. Neighbours will thus only fetch hits.

NONE
Seen with errors and cachemgr requests.

The following codes are no longer available in Squid-2:

ERR_*
Errors are now contained in the status code.

TCP_CLIENT_REFRESH
See: TCP_CLIENT_REFRESH_MISS.

TCP_SWAPFAIL
See: TCP_SWAPFAIL_MISS.

TCP_IMS_MISS
Deleted, TCP_IMS_HIT used instead.

UDP_HIT_OBJ
Hit objects are no longer available.

UDP_RELOADING
See: UDP_MISS_NOFETCH.

Http Status Codes

000 Used mostly with UDP traffic.

100 Continue
101 Switching Protocols
*102 Processing

200 OK
201 Created
202 Accepted
203 Non-Authoritative Information
204 No Content
205 Reset Content
206 Partial Content
*207 Multi Status

300 Multiple Choices
301 Moved Permanently
302 Moved Temporarily
303 See Other
304 Not Modified
305 Use Proxy
[307 Temporary Redirect]

400 Bad Request
401 Unauthorized
402 Payment Required
403 Forbidden
404 Not Found
405 Method Not Allowed
406 Not Acceptable
407 Proxy Authentication Required
408 Request Timeout
409 Conflict
410 Gone
411 Length Required
412 Precondition Failed
413 Request Entity Too Large
414 Request URI Too Large
415 Unsupported Media Type
[416 Request Range Not Satisfiable]
[417 Expectation Failed]
*424 Locked
*424 Failed Dependency
*433 Unprocessable Entity

500 Internal Server Error
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Timeout
505 HTTP Version Not Supported
*507 Insufficient Storage

600 Squid header parsing error

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