elvtune(8)
NAME
elvtune - I/O elevator tuner
SYNOPSIS
elvtune [ -r r_lat ] [ -w w_lat ] [ -b b_max ] /dev/blkdev1 [ /dev/blkdev2 ... ] elvtune -h elvtune -v
DESCRIPTION
- elvtune allows to tune the I/O elevator per blockdevice
- queue basis. The tuning can be safely done at runtime. Tuning the
- elevator means being able to change disk performance and interac
- tiveness. In the output of elvtune the address of the queue tuned
- will be shown and it can be considered as a queue ID. For exam
- ple multiple partitions in the same harddisk will share the same
- queue and so tuning one partition will be like tuning the whole
- HD.
OPTIONS
- -r r_lat
- set the max latency that the I/O scheduler will
- provide on each read.
- -w w_lat
- set the max latency that the I/O scheduler will
- provide on each write.
- -b b_max
- max coalescing factor allowed on writes when there
- are reads pending in the queue.
- -h help.
- -v version.
NOTE
- Actually the only fields tunable are those relative to the
- IO scheduler. It's not possible to select a one-way or two-way
- elevator yet.
- For logical blockdevices like LVM the tuning has to be
- done on the physical devices. Tuning the queue of the LVM logical
- device is useless.
RETURN VALUE
0 on success and 1 on failure.
HISTORY
- Ioctls for tuning elevator behaviour were added in Linux
- 2.3.99-pre1.
AUTHORS
- Andrea Arcangeli <andrea@suse.de> SuSE
- Version 1.0 14 March 2000