[OpenAFS] pre-fetch cache

[Jeffrey Altman]

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Brian May wrote:
> The replicated copy could be installed on a fast LAN when the master
> server is on a slower WAN.

This is what replicated read-only volumes are for.

> Examples of large files could include video files, CAD designs, etc.

These are items that change infrequently and are appropriate for
distribution via read-only volumes.

> The argument was "we don't want to load the network during peak
> periods". I suspect not much thought was put into this.

You will have heavy loads under two circumstances:

(1) the content of the data on the servers change

(2) the quantity of data you are accessing from the network exceeds the
size of the cache.

> Am I correct in my understanding of AFS that any file writes require
> the entire file be copied back to the master server as soon as the
> program calls close() on that file? I think my client forgot to
> consider this.

Or when the cache needs to flush dirty pages.

> I guess I should go back to the client to clarify requirements and
> bring some sort of reality into the discussion. I don't know of
> anything that meets their requirements, but I think AFS is the closest
> I have seen.

Probably a good idea.


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