cacheFS

[Steve Dickson]

Ido Levy wrote:
> nfsv4-bounces at linux-nfs.org wrote on 26/02/2008 19:54:39:
> 
>>
>> Ido Levy wrote:
>>> Hello,
>>>
>>> We are  testing cacheFS on Linux RHEL 5.1 client that use NFS to mount
> a
>>> remote storage.
>>> We follow the documentation at  /usr/share/doc/cachefilesd-0.8 and set
> the
>>> configuration accordingly.
>>>
>>> We are trying to figure out if the cache is used after a reboot by
> viewing
>>> the content of the file /proc/sys/fs/nfs/fscache_from_pages.
>>> When performing a reread operation without rebooting the machine the
> value
>>> hold by the file /proc/sys/fs/nfs/fscache_from_pages
>>> is increasing and the operation is faster.
>> fscache_from_pages are pages being read from the fscache. So this
>> make sense...
>>
>>> If we issue a reboot between the read and the reread operations the
> value
>>> of the file /proc/sys/fs/nfs/fscache_from_pages is zero
>>> and the operation time is similar to the first time we read the file
> hence
>>> the cache is not used after a reboot.
>>>
>>> Is it supposed to behave that way or we are missing something.
>> Well the cache was designed as just that a cache... so if there
>> is any type of irregularities the cache is not used. But this
>> could be a bug... Was there any type errors in /var/log/messages
>> during the reboot?
> 
> No, the only relevant messages during the reboot are::
> 
> kernel: FS-Cache: Loaded
> kernel: CacheFiles: Loaded
> kernel: FS-Cache: Cache "mycache" added (type cachefiles)
> kernel: CacheFiles: File cache on 03:01 registered
> 
> Please note that we did the following steps in order to validate the issue:
> 
> 1) Read a file for the first time and validate that it was cached.
> 2) Reboot the machine.
> 3) Read the same file ( that was not changed during reboot time ) for the
> second time.
> 
> Unfortunately the cache was not used on the second time ( after the
> reboot ).
and your sure the -o fsc mount flag is being used on the second mount
(i.e. the one after the reboot)?

steved.