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 per
formance and interactiveness. In the output of elvtune the
address of the queue tuned will be shown and it can be
considered as a queue ID. For example multiple partitions
in the same harddisk will share the same queue and so tun
ing 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.
Andrea Arcangeli <andrea@suse.de> SuSE
Man(1) output converted with
man2html