superseeded: [PATCH manager/storage 0/2] fix #7339: lvmthick: add option to free storage for deleted VMs

[Lukas Sichert <l.sichert@proxmox.com>]

superseeded-by:
https://lore.proxmox.com/all/20260416143729.54192-1-l.sichert@proxmox.com/

On 2026-03-23 11:14, Lukas Sichert wrote:
> Logical volumes (LV) in an LVM (thick) volume group (VG) are
> thick-provisioned, but the underlying backing storage can be
> thin-provisioned. In particular, this can be the case if the VG resides
> on a LUN provided by a SAN via ISCSI/FC/SAS [1], where the LUN may be
> thin-provisioned on the SAN side.
> 
> In such setups, one usually wants that deleting an LV (e.g. VM disk)
> frees up space on the SAN side, especially when using
> snapshots-as-volume-chains, because snapshot LVs are thick-provisioned
> LVs from the LVM point of view, so users may want to over-provision the
> LUN on the SAN side.
> 
> One option to free up space when deleting an LV is to set
> `issue_discards = 1` in the LVM config. With this setting, `lvremove`
> will send discards for the regions previously used by the LV, which will
> (if the SAN supports it) inform the SAN that the space is not in use
> anymore and can be freed up. Since `lvremove` modifies LVM metadata, it
> has to be issued while holding a cluster-wide lock on the storage.
> Unfortunately, depending on the setup, `issue_discards = 1` can make
> `lvremove` take very long for big disks (due to the large number of
> discards being issued), so that it eventually hits the 60s timeout of
> the cluster lock. The 60s are a hard-coded limit and cannot be easily
> changed [2].
> 
> A better option would be to use 'blkdiscard'.This will issue discard for
> all the blocks of the device and therefore free the storage on the san
> [3]. As this option does not require changing any LVM metadata it can be
> executed with a storage lock.
> 
> There is already a setting for  'saferemove', which zeros-out
> to-be-deleted LVs using 'blkdiscard --zeroout' as a worker, but it does
> not discard the blocks afterwards. This, similarly to just 'blkdiscard',
> does not require a cluster-wide lock and therefore can be executed
> without running into the 60s timeout.
> 
> This series extends the 'saferemove' worker so that he can execute
> 'blkdiscard', 'blkdiscard --zeroout' or both of them together and adds
> an option to select this in the Gui.
> 
> 
> [1] https://pve.proxmox.com/wiki/Migrate_to_Proxmox_VE#Storage_boxes_(SAN/NAS)
> [2] https://forum.proxmox.com/threads/175849/post-820043
> 
> 
> storage:
> 
> Lukas Sichert (1):
>   fix #7339: lvmthick: add worker to free space of to be deleted VMs
> 
>  src/PVE/Storage.pm           | 16 ++++++++++++----
>  src/PVE/Storage/LVMPlugin.pm | 31 ++++++++++++++++++++++---------
>  2 files changed, 34 insertions(+), 13 deletions(-)
> 
> 
> manager:
> 
> Lukas Sichert (1):
>   fix #7339: lvmthick: ui: add UI fields for option to free storage
> 
>  www/manager6/Utils.js           |  3 +++
>  www/manager6/storage/LVMEdit.js | 13 +++++++++++++
>  2 files changed, 16 insertions(+)
> 
> 
> Summary over all repositories:
>   4 files changed, 50 insertions(+), 13 deletions(-)
>