Re: [PATCH storage,cluster,manager 0/13] multipath: cluster-wide config, storage and health overview

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

Thomas Lamprecht <t.lamprecht@proxmox.com> writes:

> This is a proof of concept for better multipath support in PVE. I talked it
> over with Friedrich back in May and put it together to get early feedback,
> also because there is other multipath and iSCSI work going on (for example
> Mira's storage mapping series).
>
> [ .. ]
>
> Open points:
>
>  [ .. ]
>
>  - Upgrade and adoption: PVE rewrites /etc/multipath/wwids to match its
>    allow-list, so it drops WWIDs that PVE did not add, which is risky on nodes
>    whose multipath was set up by hand or that boot from SAN. There is also no
>    migration from an existing multipath.conf, and a no-touch guarantee for
>    boot-from-SAN devices needs thought.

These patches correctly show the existing WWIDs and their status when
installed on a node with an existing /etc/multipath/wwids.

In my testing, the "rewrite" only happens after adding a new WWID using
the new API.

If an automatic upgrade path is not possible, would it be possible to
warn the user if /etc/multipath/wwids has entries and
/etc/pve/multipath.conf does not exist when adding a new WWID? Perhaps
this is enough for the user to do a proper migration.

-- 
Maximiliano