Не, в geom есть и "продвинутый" планировщик, с 2008 анонсирован кажись.http://retis.sssup.it/~fabio/freebsd/geom_sched/proto/
# man gsched
NAME
gsched -- control utility for disk scheduler GEOM class
SYNOPSIS
gsched create [-v] [-a algorithm] provider ...
gsched insert [-v] [-a algorithm] provider ...
gsched configure [-v] [-a algorithm] node ...
gsched destroy [-fv] node ...
gsched reset [-v] node ...
gsched { list | status | load | unload }
DESCRIPTION
The gsched utility (also callable as geom sched ...) changes the schedul-
ing policy of the requests going to a provider.
...
# geom disk list
Geom name: ada0
Providers:
1. Name: ada0
Mediasize: 160041885696 (149G)
Sectorsize: 512
Mode: r6w6e23
descr: ST9160310AS
ident: (null)
fwsectors: 63
fwheads: 16
# kldload geom_sched
# geom sched insert -a rr ada0
# geom disk list
Geom name: ada0
Providers:
1. Name: ada0.sched.
Mediasize: 160041885696 (149G)
Sectorsize: 512
Mode: r6w6e23
descr: ST9160310AS
ident: (null)
fwsectors: 63
fwheads: 16
Все это только и на работающей системе. Как бэ все, шедулер вставлен. Провайдер - этот тот кто сверху и к нам ближе :)
Тестировать с цифирями долго, нужно нескольк дисков, корректно нагрузить, надо думать о корректности измерений, не готов, оставляю пока на других.
http://ivoras.net/freebsd/freebsd9.html
Generic GEOM IO schedulers
Status: Committed to -CURRENT
Will appear in 9.0: sure
Authors: Luigi Rizzo, Fabio Checconi
Web: commit message
The new framework, integrated with GEOM, allows for multiple disk IO schedulers to be used, if necessary, on different IO providers (e.g. drives). The usage of some IO schedulers can increase responsiveness in certain kinds of IO workloads, for example a mix of sequential and random IO.
http://svnweb.FreeBSD.org/base?view=revision&revision=206497
