Filesystem

Journal type

  • ordered: It is the default mode. All data is forced directly out to the main file system prior to its meta-data being committed to the journal.
  • writeback: Data ordering is not preserved, data may be written into the main file system after its metadata has been committed to the journal. This is rumored to be the highest-throughput option. It guarantees internal file system integrity, however it can allow old data to appear in files after a crash and journal recovery.
  • journal: All data is committed into the journal prior to being written into the main file system.

Mount options

defaults = (rw, suid, dev, exec, auto, nouser, async, and relatime)

I/O scheduler

  • anticipatory (RHEL 4-5)
  • noop
  • deadline
  • cfq

Commands

  • Display the scheduler for disk: cat /sys/block/<disk>/queue/scheduler
  • Change the scheduler online: echo deadline > /sys/block/<disk>/queue/scheduler
  • Change the scheduler globally (or write udev rules):

vi /etc/grub.conf

kernel.... elevator=deadline

reboot

tuned

  • Install the package: yum install tuned; chkconfig tuned on; /etc/init.d/tuned start
  • List all available profiles: tuned-adm list
  • Display the active profile: tuned-adm active
  • Change the profile (conf file - /etc/ktune.d/tunedadm.conf): tuned-adm profile virtual-host

Commands

  • Check mount options: cat /proc/mounts