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diff --git a/Feature Planning/GlusterFS 3.5/File Snapshot.md b/Feature Planning/GlusterFS 3.5/File Snapshot.md new file mode 100644 index 0000000..b2d6c69 --- /dev/null +++ b/Feature Planning/GlusterFS 3.5/File Snapshot.md @@ -0,0 +1,101 @@ +Feature +------- + +File Snapshots in GlusterFS + +### Summary + +Ability to take snapshots of files in GlusterFS + +### Owners + +Anand Avati + +### Source code + +Patch for this feature - <http://review.gluster.org/5367> + +### Detailed Description + +The feature adds file snapshotting support to GlusterFS. '' To use this +feature the file format should be QCOW2 (from QEMU)'' . The patch takes +the block layer code from Qemu and converts it into a translator in +gluster. + +### Benefit to GlusterFS + +Better integration with Openstack Cinder, and in general ability to take +snapshots of files (typically VM images) + +### Usage + +*To take snapshot of a file, the file format should be QCOW2. To set +file type as qcow2 check step \#2 below* + +1. Turning on snapshot feature : + + gluster volume set `<vol_name>` features.file-snapshot on + +2. To set qcow2 file format: + + setfattr -n trusted.glusterfs.block-format -v qcow2:10GB <file_name> + +3. To create a snapshot: + + setfattr -n trusted.glusterfs.block-snapshot-create -v <image_name> <file_name> + +4. To apply/revert back to a snapshot: + + setfattr -n trusted.glusterfs.block-snapshot-goto -v <image_name> <file_name> + +### Scope + +#### Nature of proposed change + +The work is going to be a new translator. Very minimal changes to +existing code (minor change in syncops) + +#### Implications on manageability + +Will need ability to load/unload the translator in the stack. + +#### Implications on presentation layer + +Feature must be presentation layer independent. + +#### Implications on persistence layer + +No implications + +#### Implications on 'GlusterFS' backend + +Internal snapshots - No implications. External snapshots - there will be +hidden directories added. + +#### Modification to GlusterFS metadata + +New xattr will be added to identify files which are 'snapshot managed' +vs raw files. + +#### Implications on 'glusterd' + +Yet another turn on/off feature for glusterd. Volgen will have to add a +new translator in the generated graph. + +### How To Test + +Snapshots can be tested by taking snapshots along with checksum of the +state of the file, making further changes and going back to old snapshot +and verify the checksum again. + +### Dependencies + +Dependent QEMU code is imported into the codebase. + +### Documentation + +<http://review.gluster.org/#/c/7488/6/doc/features/file-snapshot.md> + +### Status + +Merged in master and available in Gluster3.5
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