[DRBD-user] First test lab with drbd9 + linstor + Proxmox

[Robert Altnoeder]

On 08/20/2018 05:03 PM, Julien Escario wrote:
> My question was essentially about thinprov with ZFS. In recent versions
> (2018), drbdmanage is able to skip full resync at volume creation with
> ZvolThinLv2 plugin at least).

I don't remember the exact status right now, it is planned, but I think
it is not implemented yet. It might even work already, but I am pretty
sure it's not tested yet.

> Installation went fine. Just a little typo in manual, chapter 4.8 (Storage
> pools) :
> linstor create-storage-pool pool_ssd alpha lvm vg_ssd
>
> The correct syntax seems to be :
> linstor storage-pool create alpha pool_ssd lvm vg_ssd

That's a long story. As a very brief summary, LINSTOR was originally
designed to come with a radically new client that was supposed to be
able to find commands by action (like create, delete, set, ...) or by
object (like resource, volume, ...), and those commands were supposed to
follow a consistent system for naming and acronyms which would have
matched the server's native commands and the API (e.g.,
"create-storage-pool" was the long form of the "CrtStorPool" command,
which is also the name of the corresponding server API). Parameters were
supposed to be key/value instead of positional parameters, and the whole
thing would have been mostly form-based, so users would typically have
selected the command and typed in the values.

Anyway, developer resources are limited, so as of now, we still have a
rather typical command line client (it's actually a heavily adapted
variant of the drbdmanage client). Using this client, people apparently
had a hard time figuring out which objects they could create and where
to start, and so the command line client was restructured to work with
multiple levels of subcommands, where the first level is an object, not
an action. This was done in order to make the list of top-level commands
shorter.

That's how you get "storage-pool create" instead, and sometimes there
are leftovers in the documentation from before this change. We'll fix
that in the documentation.

> Another one spotted right now : "6.5. Makinging the Controller Highly-Availible"
> Should be 'making', I think.

Yes, and while we're at it, let's make this "Available". Looks like we
got 2 typos on one line here, must have been one of those days... ;)

> So I think equivalent of assign/unassign of drbdmanage is :
>
> # linstor resource delete <node> <resource> --storage-pool <pool>
> # linstor resource create <node> <resource> --storage-pool <pool>

Essentially yes, I think delete does not take the --storage-pool
parameter though.

> Is there already some kind of disconnect/reconnect command with linstore ? (I
> didn't manage to found it).

Not yet. Among the things still missing in LINSTOR are:

- automatic retries: a future version of the satellite will
automatically reschedule the creation/deletion/... task for resources
where some of the necessary actions failed

- a client command that tells the LINSTOR server to check a resource;
that typically results in LINSTOR doing a "drbdadm adjust", which will
also reconnect resources that are disconnected
(the Satellite actually has a debug command that's supposed to do that,
but there is no corresponding client command yet; last time I checked,
the Satellite debug command was inoperative due to a regression, I am
not sure whether this is fixed already in the current version)

We do not have connect/disconnect commands or attach/detach commands on
the roadmap as of now, but might consider them in the future (we simply
have not made up our mind regarding that yet).

br,
Robert