scurrier
Patron
- Joined
- Jan 2, 2014
- Messages
- 297
ZFS has an IO scheduler that dispatches IO requests to leaf vdevs depending on the class of the file system IO to be satisfied. The class of filesystem IO is one of the following and is prioritized in this order:
sync read
sync write
async read
async write
scrub/resilver
Each class has a corresponding min and max active outstanding requests number that is sought to be fulfilled by the scheduler.
Is there any diagnostic tool for viewing the number of each class of these requests on a running system?
-- For Posterity --
This scheme is more fully described in the source code comments here.
These tunables control the balance of scheduling:
sync read
sync write
async read
async write
scrub/resilver
Each class has a corresponding min and max active outstanding requests number that is sought to be fulfilled by the scheduler.
Is there any diagnostic tool for viewing the number of each class of these requests on a running system?
-- For Posterity --
This scheme is more fully described in the source code comments here.
These tunables control the balance of scheduling:
vfs.zfs.vdev.max_active
vfs.zfs.vdev.sync_read_min_active
vfs.zfs.vdev.sync_read_max_active
vfs.zfs.vdev.sync_write_min_active
vfs.zfs.vdev.sync_write_max_active
vfs.zfs.vdev.async_read_min_active
vfs.zfs.vdev.async_read_max_active
vfs.zfs.vdev.async_write_min_active
vfs.zfs.vdev.async_write_max_active
vfs.zfs.vdev.scrub_min_active
vfs.zfs.vdev.scrub_max_active