Difference between revisions of "HowTo Disable The "relatime" Method For File "atime" Updates"
(→'''atime''') |
(→'''atime''') |
||
| Line 3: | Line 3: | ||
=='''atime'''== | =='''atime'''== | ||
| − | The "'''Access time'''" field for a file within a given file system is know as: "'''atime'''". When a process reads a file, the "'''atime'''" field is updated with the current date/time for this access. <i>Disabling</i> "'''atime'''" updates using the "'''noatime'''" mount flag is probably one of the biggest performance tweak that a '''Linux''' administrator can make. An active '''Linux''' server is continually reading files which generates | + | The "'''Access time'''" field for a file within a given file system is know as: "'''atime'''". When a process reads a file, the "'''atime'''" field is updated with the current date/time for this access. <i>Disabling</i> "'''atime'''" updates using the "'''noatime'''" mount flag is probably one of the biggest performance tweak that a '''Linux''' administrator can make. An active '''Linux''' server is continually reading files which generates a significant number of "'''atime'''" updates. This translates to <i>numerous</i> metadata updates made to the file system by writes to the physical disk which can lead to poor I/O performance. |
=='''relatime'''== | =='''relatime'''== | ||
Relative atime ('relatime') only updates the atime if the previous atime is older than the mtime or ctime. It avoids a lot of metadata atime updates (but not all of them, obviously, there's 'noatime' for that). It's like noatime, but useful for applications like mutt that need to know when a file has been read since it was last modified. | Relative atime ('relatime') only updates the atime if the previous atime is older than the mtime or ctime. It avoids a lot of metadata atime updates (but not all of them, obviously, there's 'noatime' for that). It's like noatime, but useful for applications like mutt that need to know when a file has been read since it was last modified. | ||
Revision as of 17:33, 4 August 2008
Overview
atime
The "Access time" field for a file within a given file system is know as: "atime". When a process reads a file, the "atime" field is updated with the current date/time for this access. Disabling "atime" updates using the "noatime" mount flag is probably one of the biggest performance tweak that a Linux administrator can make. An active Linux server is continually reading files which generates a significant number of "atime" updates. This translates to numerous metadata updates made to the file system by writes to the physical disk which can lead to poor I/O performance.
relatime
Relative atime ('relatime') only updates the atime if the previous atime is older than the mtime or ctime. It avoids a lot of metadata atime updates (but not all of them, obviously, there's 'noatime' for that). It's like noatime, but useful for applications like mutt that need to know when a file has been read since it was last modified.
