Darren Reed wrote:
> Nicolas Williams wrote:
>
>> ...
>>
>>> It would be nice to see a commitment to closing any remaining gap as
>>> much as possible, perhaps by further development of NFSv4 -- as
>>> others have suggested.
>>>
>>> As a final note, I do recall that cachefs was supposed to be generic
>>> for things like cdroms, etc. I do agree with the proposal that
>>> cachefs like behavior for anything *other than NFS* is probably not
>>> terribly interesting.
>>>
>>
>> I don't. cachefs like behaviour could be useful for CIFS as well (and
>> some day WebDAV too, why not, and maybe the AFS community would use the
>> infrastructure if available).
>>
>> The problem with cachefs is that it needs to be a service provided to
>> filesystems that filesystems must use explicitly.
>>
>>
>
> To me it sounds like you are saying that cachefs is a nice answer
> but that its current architecture isn't suitable for a role more
> wisespread than just NFS. Given this we may as well EOL cachefs
> and replace it at some point in the future with a feature that does
> a better job of caching any network based filesystem, not just NFS,
> right?
The problem here is that cachefs is not generic caching solution as of now,
It is agreed that we need a persistent caching need for the network
based filesystem,
but retaining cachefs to provide that functionality is a support nightmare
- Current code is not generic and uses suboptimal use of generic
kernel functions.
- knows a lot about UFS (local cache) and NFS v2 and v3
- Can't work with NFS v4 (becauase of (2)) and changes required to
make it
seemlessly work with NFS v4 is almost like a new project.
While having a requirement to provide persistent cache for certain workload
is a good idea, its the consistency that suffers today with cachefs when
pushed to an environment
where multiple clients modify the data on the server.
I think the current code is unmaintainable, I suggest any new request
for providing persistent
cache for Network filesystems should be handled via a new project.
cachefs is not suitable
for these kind of modifications at the moment.
Regards
Kiran
