From 9622c1cbeca5753c3c1acc074dad71ad62b81b2d Mon Sep 17 00:00:00 2001 From: Maciej Szwed Date: Tue, 18 Jun 2019 14:34:36 +0200 Subject: [PATCH] blobstore/docs: Documentation for 'delete snapshot' functionality Signed-off-by: Maciej Szwed Change-Id: I0e135b8e74f6396935c3a4744149f907b9988ece Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/458461 Tested-by: SPDK CI Jenkins Reviewed-by: Changpeng Liu Reviewed-by: Darek Stojaczyk --- CHANGELOG.md | 4 ++++ doc/lvol.md | 3 +++ 2 files changed, 7 insertions(+) diff --git a/CHANGELOG.md b/CHANGELOG.md index 2d827a354..5bb3f342c 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -105,6 +105,10 @@ Added thread_get_stats RPC method to retrieve existing statistics. Added nvmf_get_stats RPC method to retrieve NVMf susbsystem statistics. +### blobstore + +A snapshot can now be deleted if there is only a single clone on top of it. + ## v19.04: ### nvme diff --git a/doc/lvol.md b/doc/lvol.md index 78365ba77..ba59677c2 100644 --- a/doc/lvol.md +++ b/doc/lvol.md @@ -57,6 +57,9 @@ The write operation is performed as shown in the diagram below: User may also create clone of existing snapshot that will be thin provisioned and it will behave in the same way as logical volume from which snapshot is created. There is no limit of clones and snapshots that may be created as long as there is enough space on logical volume store. Snapshots are read only. Clones may be created only from snapshots or read only logical volumes. +A snapshot can be removed only if there is a single clone on top of it. The relation chain will be updated accordingly. The cluster map of clone and snapshot will be merged and entries for unallocated clusters in the clone +will be updated with addresses from the snapshot cluster map. The entire operation modifies metadata only - no data is copied during this process. + ## Inflation {#lvol_inflation} Blobs can be inflated to copy data from backing devices (e.g. snapshots) and allocate all remaining clusters. As a result of this operation all dependencies for the blob are removed.