Re: [pve-devel] [PATCH docs] storage: note that qcow2 internal snapshots are inefficient

[Fiona Ebner <f.ebner@proxmox.com>]

Am 28.11.25 um 4:56 PM schrieb Fiona Ebner:
> It's a commonly reported issue, most recently again in the enterprise
> support, that taking or removing snapshots of large qcow2 files on
> file-based network storages can take a very long time. Add a note
> about this limitation.
> 
> Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
> ---
>  pvesm.adoc | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/pvesm.adoc b/pvesm.adoc
> index d36baf8..165b446 100644
> --- a/pvesm.adoc
> +++ b/pvesm.adoc
> @@ -88,6 +88,11 @@ block device functionality.
>  
>  ^2^: On file based storages, snapshots are possible with the 'qcow2' format,
>  either using the internal snapshot function, or snapshots as volume chains^4^.
> +Creating and deleting internal 'qcow2' snapshots will block a running VM and
> +is not an efficient operation. The performance is particularly bad with network
> +storages like NFS. On some setups and for large disks (multiple hundred GiB or
> +TiB sized), these operations may take several minutes, or in extreme cases, even
> +hours.
>  
>  ^3^: It is possible to use LVM on top of an iSCSI or FC-based storage.
>  That way you get a `shared` LVM storage

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