Provided by: util-linux_2.12r-4ubuntu6_i386 bug

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  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 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