Re: [LAU] Ext3 or JFS (or other) for linux audio?

From: James Cameron <quozl@email-addr-hidden>
Date: Thu Sep 10 2009 - 06:45:20 EEST

On Wed, Sep 09, 2009 at 03:08:58PM +0200, Arnold Krille wrote:
> I think for plain recording it shouldn't make a difference. When
> playback occurs, there are multiple files involved and it could be the
> seeks also depend on how the file systems lays out the files on disk.
> So that might have an influence. If this information isn't cached in
> ram.

Yes, the ideal is that the tracks being played are cached in RAM so that
no disk access is required. The recording track would be creating a
file that would be periodically written to disk.

(LWN handled something relevant to this today, in an article by Valerie,
subscriber only content at the moment but I imagine it will become free
in a couple of weeks from now ... http://lwn.net/Articles/351422/ ...
but the interesting thing there was that with ext3 and data=ordered,
data reaches disk within about five seconds by default ... and in the
previous article http://lwn.net/Articles/322823/ which is freely
available, is the mention of /proc/sys/vm/dirty_writeback_centisecs ...
for a multitrack studio scenario with backup power I'd increase this
value immediately prior to commencing the recording, so as to encourage
any writes to be buffered ... and restore it to default on transport
stop).

Actually, an even better ideal is to have a hard disk for each track,
and use a filesystem with delayed allocation ... this would minimise the
latency on the track read requests, and keep the disk heads sitting over
the area they will be next needed.

-- 
James Cameron
http://quozl.linux.org.au/
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Received on Thu Sep 10 08:15:02 2009

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