[fuse-devel] When to flush cache

[Nikolaus R. <Nik...@ra...>]

Hello,

I am working on a network filesystem and I am interested in your
opinions about cache flushing strategies.

At the moment, I am flushing the cache whenever a file is closed (i.e.
when flush() is called) and when I need to free some cache space to
retrieve new data.

I was wondering whether it might be a good idea to additionally flush
the cache periodically, e.g. to flush all cache blocks that have not
been accessed for 5 seconds.

This would have the advantage that the network connection is utilized
as soon as the filesystem is mounted, and not only after the first
file has been written completely (it could be large) or we run out of
cache space (that could be rather larger as well). 


The drawback is of course related to that: I may fill up the network
connection with transmitting "useless" data that I need to retransmit
later, thus consuming bandwidth and (expensive) traffic volume.


What would you do?



I am rather opposed to simply making this configurable, because if I'm
unsure myself (and I know how my fs works) how can I expect the user
to decide this?


Best,


   -Nikolaus

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