volume copy bandwidth limit shouldn't applied to temporal file on local disks

[Tomoki Sekiyama]

When volume copy bandwidth limit (volume_copy_bps_limit config option) is enabled, every block devices will be a target of volume copy throttling. However, in some environments, it would not be appropriate to throttle local disks (which is not used for Cinder volumes). To avoid unnecessary throttling, we should be able to set a list of 'no limit devices' which will not be throttled.

[John Griffith (john-griffith)]

Can we do an inclusive list instead of exclusive? Even better, why can't we automate this based on the volume group info (something like PVS)?

[Tomoki Sekiyama (tsekiyama)]

Thanks for the comment.

I'm afraid it is difficult to make inclusive list because new block devices may be added when the new volume is created.

As for automation, since which disk should be throttled differs on various setup (e.g. booting from bare partition, or from LVM, or from storage volume, and what backend driver is used in cinder, so on…), I'm not sure what is the 'always right' way to do it.
As the volume copy throttling is disabled by default, I think administrators who enables it can also understand how this should be configured in their environments.

[John Griffith (john-griffith)]

Not sure I follow... if we set the throttling on the raw block device we don't care in this case. Are you looking at this specifically from the viewpoint of using only the "local_block" device driver?

[Tomoki Sekiyama (tsekiyama)]

Ah sorry about confusion. I meant a boot disk by 'local disk'.
For example, with LVM-iSCSI driver, admin may want to throttle the copy of disk device for LVM, but not to throttle another device mounted on /tmp/. Or, may want to throttle FC disk, but not SATA(local) drive. (Or may want every disk when the cinder node is booting from FC disk.)

[OpenStack Infra (hudson-openstack)]

Change abandoned by Duncan Thomas (<email address hidden>) on branch: master
Review: https://review.openstack.org/109138
Reason: Abandoning change: No update for more than 14 days

[Sean McGinnis (sean-mcginnis)]

Automatically unassigning due to inactivity.