Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 20 Feb 1998 18:21:39 +0000
From:      Karl Pielorz <kpielorz@tdx.co.uk>
To:        hackers@FreeBSD.ORG
Subject:   CD-ROM filesystems / read ahead / caching...
Message-ID:  <34EDC9B3.AAF5A8AC@tdx.co.uk>

next in thread | raw e-mail | index | archive | help
Is it possible to set read aheads / caching parameters for cd9660 file systems
/ mounted CD's under FreeBSD?

I have 2 x 7 CD-ROM jukeboxes which I mount (and share out via samba) - with
the usual 'thrashing' that occurs when 2 people go for 2 CD's on the same
drive but in different changer bays...

I don't expect the file systems to do anything like delay reads to the second
LUN until the 1st one is finished (after all, how would they know that without
nasty time-outs etc. :-) - that's a bit beyond the scope of a fs I guess...
<g> - But I don't mind 'wasting' memory on say caching data, or setting very
large read-aheads (e.g. 128k/256k).

The box has a good 20Mb of RAM it can afford to burn on file system caching
(OK, when I say 'burn' I mean I would like to tell it to use 20 Mb of physical
RAM for CD-ROM cache buffers ;-) - I realise the system will allocate RAM and
use it for caching 'as it sees best' - I just want to skew it a bit...

Samba will let me set a read ahead of 16k, but I was wondering if there's
anything that can be done in the filesystem area that would improve on this?

Both units are seen as 2 SCSI ID's with 7 LUN's each, and appear as /dev/cd0a
through cd13a etc.

Regards,

Karl Pielorz

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?34EDC9B3.AAF5A8AC>