From 188b5c8d3b6815cd8f390a2b0dc7d0cdcc339ee2 Mon Sep 17 00:00:00 2001 From: Wei Zhou Date: Wed, 7 Oct 2026 09:21:48 +0200 Subject: [PATCH] Add note on RBD volume snapshots when snapshot.backup.to.secondary is false --- source/adminguide/storage.rst | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/source/adminguide/storage.rst b/source/adminguide/storage.rst index e9f9548753..d979d322c1 100644 --- a/source/adminguide/storage.rst +++ b/source/adminguide/storage.rst @@ -1351,6 +1351,12 @@ to a different directory in the same primary storage as the volume; if it is tru to the secondary storage. If the snapshot is being taken in a file-based storage (NFS, SharedMountPoint, Local), it will be copied directly to its final storage location, according to the configuration. +.. note:: + If ``snapshot.backup.to.secondary`` is false and the volume is on RBD (Ceph) primary storage, the Volume + Snapshots are kept in the storage layer, as RBD snapshots of the volume's image. Deleting such a volume + will therefore first delete all of its Volume Snapshots, as an RBD image cannot be removed while it still + has snapshots. + Since 4.21.0.0, ACS supports incremental snapshots for the KVM hypervisor when using file-based storage (NFS, SharedMountPoint, Local), to enable incremental snapshots the ``kvm.incremental.snapshot`` configuration must be enabled. Furthermore, in order to take incremental snapshots the KVM host must have at least Libvirt version 7.6.0+ and qemu version 6.1+. The size of the snapshot chains