Libvirt-Enable suppport for discard option for disks managed by nova
This blueprint aims to support specifying the discard option for disks managed by nova.
[Background]
Newer SCSI devices support UNMAP command that is used to return the unused/freed blocks back to the storage.
This command is typically useful when the storage is thin provisioned like a thin provisioned SCSI LUN.
ATA SPEC has a similar command called "Trim" command.
Qemu1.5 has supported setting discard option for the disk. In Qemu1.6, qcow2 format file supported discard too.
[Benefit for the user]
1.
Useful for the storage to recycle the unused block in thin provision case.
2.
For the volume based on SSD, it may be useful for improving the performance and prolong the lifetime of SSD.
(As i know, ext3 doesn't support discard option for mount. User needs to issuse fstrim command by hand.)
[Usage]
Support the user to specify the discard metadata for a volume or a image.
Such as:
"
hw_disk_
"
[Todo]
1. support discard option for disk in libvirt driver.
Blueprint information
- Status:
- Complete
- Approver:
- John Garbutt
- Priority:
- Low
- Drafter:
- boh.ricky
- Direction:
- Approved
- Assignee:
- boh.ricky
- Definition:
- Approved
- Series goal:
- Accepted for juno
- Implementation:
-
Implemented
- Milestone target:
-
2014.2
- Started by
- boh.ricky
- Completed by
- Michael Still
Related branches
Related bugs
Sprints
Whiteboard
Removed from next, as next is now reserved for near misses from the last milestone --johnthetubagu
If you are still working on this, please re-submit via nova-specs. If not, please mark as obsolete, and add a quick comment to describe why. --johnthetubaguy (20th April 2014)
Gerrit topic: https:/
Addressed by: https:/
Libvirt-Enable suppport for discard option for disk device
Gerrit topic: https:/
Addressed by: https:/
Libvirt-Enable suppport for discard option for disk device
Has a +2, so leaving in juno for now. --johnthetubaguy 2nd September 2014
Sorry, this has not yet been approved, so this will have to wait until kilo. Please contact me on IRC, or via email, for more details. Thank you. --johnthetubaguy 3rd September 2014
FFE granted --johnthetubaguy 8th September 2014
