Mailing List Archive: Antw: resource-agents: exportfs: Unlocking filesystems on stop by default

Antw: resource-agents: exportfs: Unlocking filesystems on stop by default

Mar 11, 2014, 4:37 AM

Post #1 of 3 (1239 views)

Hi!

I'm wondering: Does "unlock" mean that all file locks are invalidated? If so,
I think it's a bad idea, because for a migration of the NFS server the exports
will be stopped/started, thus loosing all locks. That's not what a HA
NFS-Server should do. HA NFS-Servers try hard to preserve locks.

Regards,
Ulrich Windl

>>> Kristoffer GrÃ¶nlund<kgronlund@suse.com> schrieb am 11.03.2014 um 11:37 in
Nachricht <20140311113711.2bf52a63@ultralix>:
> Hi,
>
> I have created a submit request for the NFS exportfs agent to change
> the default for the parameter unlock_on_stop from 0 to 1.
>
> The resource agent should really release all locks which the NFS server
> holds when stopping the resource. When this option was introduced, the
> default was kept as 0 for compatibility reasons with legacy kernels,
> existing users and non-Linux systems.
>
> There has been a bit of discussion in the submit request whether
> changing the default makes sense, and right now things are leaning
> towards making the change. [1]
>
> Are there any objections from anyone else?
>
> [1]: https://github.com/ClusterLabs/resource-agents/pull/394
>
> Thanks,
>
> --
> // Kristoffer GrÃ¶nlund
> // kgronlund@suse.com
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> Linux-HA@lists.linux-ha.org
> http://lists.linux-ha.org/mailman/listinfo/linux-ha
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Re: Antw: resource-agents: exportfs: Unlocking filesystems on stop by default [ In reply to ]

lmb at suse

Mar 11, 2014, 4:45 AM

Post #2 of 3 (1168 views)

Permalink

On 2014-03-11T12:37:39, Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de> wrote:

> I'm wondering: Does "unlock" mean that all file locks are invalidated? If so,
> I think it's a bad idea, because for a migration of the NFS server the exports
> will be stopped/started, thus loosing all locks. That's not what a HA
> NFS-Server should do. HA NFS-Servers try hard to preserve locks.

No. Specifically, this feature was explicitly designed for HA take-over:
http://people.redhat.com/rpeterso/Patches/NFS/NLM/004.txt

Regards,
Lars

--
Architect Storage/HA
SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB 21284 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde

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Re: Antw: resource-agents: exportfs: Unlocking filesystems on stop by default [ In reply to ]

Ulrich.Windl at rz

Mar 11, 2014, 7:48 AM

Post #3 of 3 (1163 views)

Permalink

>>> Lars Marowsky-Bree <lmb@suse.com> schrieb am 11.03.2014 um 12:45 in
Nachricht
<20140311114553.GK13959@suse.de>:
> On 2014-03-11T12:37:39, Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>
wrote:
>
>> I'm wondering: Does "unlock" mean that all file locks are invalidated? If
> so,
>> I think it's a bad idea, because for a migration of the NFS server the
> exports
>> will be stopped/started, thus loosing all locks. That's not what a HA
>> NFS-Server should do. HA NFS-Servers try hard to preserve locks.
>
> No. Specifically, this feature was explicitly designed for HA take-over:
> http://people.redhat.com/rpeterso/Patches/NFS/NLM/004.txt

So if I understand it correctly, the machanism applies where the nfsd is kept
running while the exports, ip addresses and filesystems underneeth change.
Right? This is only one scenario how to do it. I'm also wonering how a matching
cluster configuration would look like.

>
>
>
> Regards,
> Lars
>
> --
> Architect Storage/HA
> SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix ImendÃ¶rffer,

> HRB 21284 (AG NÃ¼rnberg)
> "Experience is the name everyone gives to their mistakes." -- Oscar Wilde
>
> _______________________________________________
> Linux-HA mailing list
> Linux-HA@lists.linux-ha.org
> http://lists.linux-ha.org/mailman/listinfo/linux-ha
> See also: http://linux-ha.org/ReportingProblems

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