Lustre discuss - Aug 2008 - Lustre interoperability between the various 1.6.x releases

Hi,

regarding the Lustre interoperability between the various 1.6.x releases 
the manual currently says this:

13.1 Lustre Interoperability

For Lustre 1.6.4, the following upgrades are supported:
[...]
* One minor version to the next (for example, 1.6.3 > 1.6.4 and 1.4.11 > 
  1.4.12).

Could someone please elaborate on this?

1. Is it generally okay(^1) to upgrade the patchless clients to 1.6.x+1
   while the servers are still at 1.6.x?

2. Is it generally okay to upgrade the servers to 1.6.5.x+1 while some
   of the patchless clients are still at 1.6.x?

My understanding is that both is allowed and supported. Correct?

3. Is there any required/recommended upgrade order between MDSes and
   OSSes doing a rolling upgrade from 1.6.x to 1.6.x+1? (Especially
   when there are active clients)

Basically my question is this: Which version combinations between clients, 
MDSes and OSSes are allowed and which are not?

Thanks in advance!

Regards,
Karsten

^1: Appart from bugs like
    https://bugzilla.lustre.org/show_bug.cgi?id=16237

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On Aug 06, 2008  10:29 +0200, Karsten Weiss wrote:
> regarding the Lustre interoperability between the various 1.6.x releases 
> the manual currently says this:
> 
> 13.1 Lustre Interoperability
> 
> For Lustre 1.6.4, the following upgrades are supported:
> [...]
> * One minor version to the next (for example, 1.6.3 > 1.6.4 and 1.4.11
>
>   1.4.12).
> 
> Could someone please elaborate on this?
> 
> 1. Is it generally okay(^1) to upgrade the patchless clients to 1.6.x+1
>    while the servers are still at 1.6.x?
> 
> 2. Is it generally okay to upgrade the servers to 1.6.5.x+1 while some
>    of the patchless clients are still at 1.6.x?
> 
> My understanding is that both is allowed and supported. Correct?
Yes this is generally supported.  The bug you reference is unfortunate,
because it only shows up after a prolonged idle period on a client, and
when we are testing version interoperability the clients are busy running
tests, so this was missed.
> 3. Is there any required/recommended upgrade order between MDSes and
>    OSSes doing a rolling upgrade from 1.6.x to 1.6.x+1? (Especially
>    when there are active clients)
Generally servers are upgraded before clients, but that is not a hard
requirement for 1.6.x to 1.6.x+1.  In some cases we will require strict
server-before-client upgrades for e.g. 1.8.x->2.0.0, but that will be
documented in the release notes.
> Basically my question is this: Which version combinations between clients, 
> MDSes and OSSes are allowed and which are not?
The hope is that any 1.6.x client/server will work with any 1.4.6+ or
1.8.x client/server.  Due to limited testing resources we cannot possibly
test every combination of client/server versions, so we only claim support
for 1.4.latest to 1.6.x, and 1.6.x to 1.6.x+1 interoperability.  Some
customers run a diverse range of clients & servers together, YMMV.
> ^1: Appart from bugs like
>     https://bugzilla.lustre.org/show_bug.cgi?id=16237
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.