doc: clarified subvol in shallow-ro-vol.md

instead of subvol, subvolume has been used for consistency across
the doc

Signed-off-by: Humble Chirammal <hchiramm@redhat.com>
This commit is contained in:
Humble Chirammal 2022-01-31 10:12:33 +05:30 committed by mergify[bot]
parent e1cbd90c0b
commit 66f8a51c93

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@ -58,7 +58,7 @@ Key points:
* No actual new subvolumes are created in CephFS.
* The resulting volume is a reference to the source subvolume snapshot. This
reference would be stored in `Volume.volume_context` map. In order to
reference a snapshot, we need subvol name and snapshot name.
reference a snapshot, we need subvolume name and snapshot name.
* Mounting such volume means mounting the respective CephFS subvolume and
exposing the snapshot to workloads.
* Let's call a *shallow read-only volume with a subvolume snapshot as its data
@ -73,7 +73,7 @@ a shallow volume is created, what would happen if:
exists?_
This shouldn't be a problem already. The parent volume has either
`snapshot-retention` subvol feature in which case its snapshots remain
`snapshot-retention` subvolume feature in which case its snapshots remain
available, or if it doesn't have that feature, it will fail to be deleted
because it still has snapshots associated to it.
* _Source snapshot from which the shallow volume originates is removed while
@ -256,16 +256,15 @@ Volume context `Volume.volume_context`:
[`NodeStageVolume`, `NodeUnstageVolume` section](#NodeStageVolume-NodeUnstageVolume)
, snapshots cannot be mounted directly. How do we pass in path to the parent
subvolume?
* a) Path to the snapshot is passed in via `subvolumePath` / `rootPath`,
e.g.
`/volumes/<VOLUME NAME>/<SUBVOLUME NAME>/<UUID>/.snap/<SNAPSHOT NAME>`.
From that we can derive path to the subvolume: it's the parent of `.snap`
* a) Path to the snapshot is passed in via `subvolumePath` / `rootPath`, e.g.
`/volumes/<VOLUME NAME>/<SUBVOLUME NAME>/<UUID>/.snap/<SNAPSHOT NAME>`. From
that we can derive path to the subvolume: it's the parent of `.snap`
directory.
* b) Similar to a), path to the snapshot is passed in via `subvolumePath` /
`rootPath`, but instead of trying to derive the right path we introduce
another volume context parameter containing path to the parent subvolume
explicitly.
* c) `subvolumePath` / `rootPath` contains path to the parent subvolume and
we introduce another volume context parameter containing name of the
snapshot. Path to the snapshot is then formed by appending
* c) `subvolumePath` / `rootPath` contains path to the parent subvolume and we
introduce another volume context parameter containing name of the snapshot.
Path to the snapshot is then formed by appending
`/.snap/<SNAPSHOT NAME>` to the subvolume path.