Re: [PATCH docs 2/2] pvesm: update features for LVM,iSCSI,FC,SAS

[Maximiliano Sandoval <m.sandoval@proxmox.com>]

Aaron Lauterer <a.lauterer@proxmox.com> writes:

> And reword the footnotes to mention the multipath guide that show to set
> it up with LVM on top in detail.
>
> Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
> ---
>  pvesm.adoc | 17 +++++++++--------
>  1 file changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/pvesm.adoc b/pvesm.adoc
> index b43ca42..5bd24b2 100644
> --- a/pvesm.adoc
> +++ b/pvesm.adoc
> @@ -77,9 +77,9 @@ nodes that can be accessed as RBD (RADOS Block Device).
>  |CephFS         |cephfs      |file   |yes   |yes      |yes
>  |LVM            |lvm         |block  |no^3^ |yes^4^   |yes
>  |LVM-thin       |lvmthin     |block  |no    |yes      |yes
> -|iSCSI/kernel   |iscsi       |block  |yes   |no       |yes
> -|iSCSI/libiscsi |iscsidirect |block  |yes   |no       |yes
> -|FC/SAS         |native^6^   |block  |yes   |yes^4^   |yes
> +|iSCSI/kernel   |iscsi       |block  |yes^3^|yes^4^   |yes
> +|iSCSI/libiscsi |iscsidirect |block  |yes^3^|yes^4^   |yes

Technically, neither iSCSI storage plugin supports snapshots, what
supports snapshots is a LVM storage on top of a iSCSI block device. I
would personally keep the `no` and add a footnote saying that it is
possible to have snapshots on a LVM storage with savc on top of the
iSCSI storage.

> +|FC/SAS         |native^6^   |block  |yes^3^|yes^4^   |yes
>  |Ceph/RBD       |rbd         |block  |yes   |yes      |yes
>  |ZFS over iSCSI |zfs         |block  |yes   |yes      |yes
>  |========================================================================
> @@ -96,8 +96,11 @@ TiB sized), these operations may take several minutes, or in extreme cases, even
>  hours. If your setup is affected, create and remove snapshots while the VM is
>  shut down, expecting a long task duration.
>  
> -^3^: It is possible to use LVM on top of an iSCSI or FC-based storage.
> -That way you get a `shared` LVM storage
> +^3^: With iSCSI, FibreChannel (FC), or SAS block storage as shared storage in a
> +cluster, LVM is used to split the LUN into virtual disks. The
> +https://pve.proxmox.com/wiki/Multipath[Multipath Guide] explains how to
> +configure it in a cluster, including multipathing which is usually a
> +requirement in these scenarios.
>  
>  ^4^: Since {pve} 9, snapshots as a volume chain have been available for VMs.
>  These snapshots use separate volumes for the snapshot data and layer them.  For
> @@ -107,9 +110,7 @@ xref:pvesm_lvm_config[LVM configuration] section.
>  ^5^ Technology preview with best-effort support.
>  
>  ^6^ Fibre Channel (FC) and SAS block storage is handled directly by the host
> -without a dedicated storage plugin. The
> -https://pve.proxmox.com/wiki/Multipath[Multipath Guide] explains how to set it
> -up in a cluster.
> +without a dedicated storage plugin.
>  
>  
>  Thin Provisioning

-- 
Maximiliano