[CentOS] Persistent NFS Caching

Paul Berger subsolar at dimpixels.org
Wed Dec 2 14:47:42 UTC 2009


On Wed, Dec 2, 2009 at 8:08 AM, James Pearson
<james-p at moving-picture.com> wrote:
> Ray Van Dolson wrote:
>> On Tue, Dec 01, 2009 at 05:09:31PM -0600, Paul Berger wrote:
>>
>>>Has anybody got persistent NFS caching to work after 5.3 update
>>>removed the tech preview?
>>>
>>>I have cachesfilesd installed & running and using nfs-utils with fsc
>>>patched back in but it appears to not be working, any pointers?
>>
>> I can't find the link, but I thought the kernel components required for
>> FS-Cache to function were pulled in the 5.3 kernel...
>
> <https://bugzilla.redhat.com/show_bug.cgi?id=481579>
>
>> I'm not sure if they'll be back in 5.5, 6.0 or if I'm completely
>> mistaken.
>>
>> I seem to recall the delay being a result of upstream kernel not
>> accepting the FS-Cache patches (which I believe they did do recently in
>> 2.6.30).
>
> The kernel patches that were in the earlier 5.x kernels are now a bit
> out-of-date and IMHO not really suitable for production use.
>
> There has recently been a number of new FS-Cache patches/improvements
> that will be in the 2.6.32 mainline kernel
>
> I doubt FS-Cache will be back in future 5.x kernels - my guess is that
> it will be in the 6.x kernels
>
> James Pearson

I read a CentOS bugzilla http://bugs.centos.org/view.php?id=3853 that
indicated that the functionality may exist in the kernels yet, but
just the user space tools were missing. After doing some testing, the
persistent caching does not appear to be in the kernels, either that
or process outlined in the bugzilla entry and
http://people.redhat.com/steved/fscache/docs/HOWTO.txt are missing
something.

I also tried the Centos Plus kernel to see if it's be enabled in there
and the results appear to be the same.

Apparently I need to use either Fedora 12 if I want to use this
feature now, use CentOS 5.2 and not update as waiting till CentOS 6 is
not really an option.  I really hate using bleeding edge and not
updating and running with packages with know security vulnerabilities
(even on our internal networkd) seems like a poor idea. ::sigh::

Regards,
Paul Berger


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