[ovirt-devel] New SDM verb: SDM.copy_data

Hi oVirt! I wanted to take a moment to update you on a new storage verb we have in vdsm called SDM.copy_data. The purpose of this verb is to allow copying of data between various endpoints* on hosts that are not necessarily the SPM. This will allow us in the future to spread the load created by this data-intensive operation across multiple hosts while providing a better user experience than the current SPM-driven flow can. Current status (Sprint 1): - Basic SDM.copy_data is merged to vdsm - We still use the SPM host for creating the destination disk and to serially copy all volumes. - The engine Move Disk flow is being adapted to use the new verb. Patches should be merged in the next day or two. https://gerrit.ovirt.org/#/c/61087/ - New code paths must be activated by setting a config variable: "update vdc_options set option_value = true \ where option_name = 'DataOperationsByHSM';" - Currently positive flows are implemented Next steps: - Copy progress reporting in UI - Support negative flows (eg. lost contact with host) - Use this verb for live storage migration flows - Vdsm-side locking - Select a non-SPM host (when available) for copying Farther out: - Support for copy in parallel - Implement other data path verbs (eg. wipe_volume, sparsify_volume) -- Adam Litke