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

[Sergey Kulikov]

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.


-- 



 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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