Differences between version 10 and predecessor to the previous major change of LinuxIoScheduler.
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| Newer page: | version 10 | Last edited on Sunday, October 8, 2006 8:54:34 am | by GeorgePollard | Revert |
| Older page: | version 9 | Last edited on Wednesday, November 9, 2005 6:07:58 am | by SujayParekh | Revert |
@@ -32,9 +32,9 @@
The deadline scheduler implements request merging, a one-way elevator, and imposes a deadline on all operations to prevent resource starvation. Because writes return instantly within linux, with the actual data being held in cache, the deadline scheduler will also prefer readers - as long as the deadline for a write request hasn't passed. The kernel docs suggest this is the preferred scheduler for database systems, especially if you have [TCQ] aware disks, or any system with high disk performance.
! Complete Fair Queueing Scheduler ("cfq scheduler")
-The complete fair queueing scheduler implements both request merging and the elevator, and attempts to give all users of a particular device the same number of IO requests over a particular time interval. This should make it more efficient for multiuser systems. It seems that Novel SLES sets cfq as the scheduler by default.
+The complete fair queueing scheduler implements both request merging and the elevator, and attempts to give all users of a particular device the same number of IO requests over a particular time interval. This should make it more efficient for multiuser systems. It seems that Novel SLES sets cfq as the scheduler by default, as does the latest [Ubuntu] release
.
!! Changing Schedulers
The most reliable way to change schedulers is to set the kernel option 'elevator' at boot time. You can set it to one of "as", "cfq", "deadline" or "noop", to set the appropriate scheduler.
