[ovirt-users] NFS and pass discards\unmap question

[Yaniv Kaul]

On Feb 3, 2017 1:50 PM, "Nir Soffer" <nsoffer at redhat.com> wrote:

On Fri, Feb 3, 2017 at 2:29 PM, Sergey Kulikov <serg_k at msm.ru> wrote:
>
>
> Hm... maybe I need to set any options, is there any way to force ovirt to
mount with this extension, or version 4.2
> there is only 4.1 selection in "New Domain" menu.
> Current mount options:
> type nfs4 (rw,relatime,vers=4.1,rsize=65536,wsize=65536,namlen=255,
soft,nosharecache,proto=tcp,port=0,timeo=600,retrans=6,
sec=sys,local_lock=none)
>
> it should work only if forced option vers=4.2 ?
> I thought it's implemented as feature to older version, not 4.2, there is
few info about this.

Looks like ovirt engine does not allow nfs version 4.2.


But custom options can be used.
Y.


We have this RFE:
https://bugzilla.redhat.com/1406398

So practically, both sparsify and pass discard with NFS are useless
in the current version.

I think this should be fix for next 4.1 build.

Nir

>
>
> --
>
>
>
>  Friday, February 3, 2017, 14:45:43:
>
>
>
>
>
>> On Thu, Feb 2, 2017 at 11:45 PM, Sergey Kulikov <serg_k at msm.ru> wrote:
>
>
>>  I've upgraded to 4.1 release, it have great feature "Pass
>> discards", that now can be used without vdsm hooks,
>>  After upgrade I've tested it with NFS 4.1 storage, exported from
>> netapp, but unfortunately found out, that
>>  it's not working, after some investigation, I've found, that NFS
>> implementation(even 4.1) in Centos 7
>>  doesn't support sparse files and fallocate(FALLOC_FL_PUNCH_HOLE),
>> that quemu uses for file storage, it was
>>  added only in kernel 3.18, and sparse files is also announced feature
of upcoming NFS4.2,
>>  sparsify also not working on this data domains(runs, but nothing
happens).
>>
>>  This test also shows, that FALLOC_FL_PUNCH_HOLE not working, it
>> was executed on centos ovirt host with mounted nfs share:
>>  # truncate -s 1024 test1
>>  # fallocate -p -o 0 -l 1024 test1
>>  fallocate: keep size mode (-n option) unsupported
>>
>>  Is there any plans to backport this feature to node-ng, or centos? or
we should wait for RHEL 8?
>
>
>
>
>> Interesting, I was under the impression it was fixed some time ago,
>> for 7.2[1] (kernel-3.10.0-313.el7)
>> Perhaps you are not mounted with 4.2?
>
>
>> Y.
>> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1079385
>>
>>  NFS is more and more popular, so discards is VERY useful feature.
>>  I'm also planning to test fallocate on latest fedora with 4.x kernel
and mounted nfs.
>>
>>  Thanks for your work!
>>
>>  --
>>
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>
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