[pve-devel] applied: [PATCH pve-docs] Remove SCSI exclusivity from "Discard" drive option

[Thomas Lamprecht]

On 11/14/18 6:16 PM, Nick Chevsky wrote:
> This documents the recent move [1] to make the formerly SCSI-exclusive
> "Discard" option also available to IDE and SATA drives, and explains
> its dependency on either VirtIO SCSI or SSD emulation [2].
> 
> [1] https://git.proxmox.com/?p=pve-manager.git;a=commit;h=ee4b837692bf3d0f50b6cb8f29a5272e9a632430
> [2] https://git.proxmox.com/?p=pve-docs.git;a=commit;h=25203dc111c1af5a1e100246954d1467535676c7
> 
> Signed-off-by: Nick Chevsky <nchevsky at gmail.com>
> ---
>  qm.adoc | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/qm.adoc b/qm.adoc
> index 0d453c8..a15e0fe 100644
> --- a/qm.adoc
> +++ b/qm.adoc
> @@ -193,16 +193,21 @@ As of {pve} 5.0, replication requires the disk images to be on a storage of type
>  configured requires to skip replication for this disk image.
>  
>  If your storage supports _thin provisioning_ (see the storage chapter in the
> -{pve} guide), and your VM has a *SCSI* controller you can activate the *Discard*
> -option on the hard disks connected to that controller. With *Discard* enabled,
> -when the filesystem of a VM marks blocks as unused after removing files, the
> -emulated SCSI controller will relay this information to the storage, which will
> -then shrink the disk image accordingly.
> +{pve} guide), you can activate the *Discard* option on a drive. With *Discard*
> +set and a _TRIM_-enabled guest OS footnote:[TRIM, UNMAP, and discard
> +https://en.wikipedia.org/wiki/Trim_%28computing%29], when the VM's filesystem
> +marks blocks as unused after deleting files, the controller will relay this
> +information to the storage, which will then shrink the disk image accordingly.
> +For the guest to be able to issue _TRIM_ commands, you must either use a
> +*VirtIO SCSI* (or *VirtIO SCSI Single*) controller or set the *SSD emulation*
> +option on the drive. Note that *Discard* is not supported on *VirtIO Block*
> +drives.
>  
>  If you would like a drive to be presented to the guest as a solid-state drive
>  rather than a rotational hard disk, you can set the *SSD emulation* option on
>  that drive. There is no requirement that the underlying storage actually be
>  backed by SSDs; this feature can be used with physical media of any type.
> +Note that *SSD emulation* is not supported on *VirtIO Block* drives.
>  
>  .IO Thread
>  The option *IO Thread* can only be used when using a disk with the
> 

applied, thanks!