Date: Thu, 7 Nov 2002 12:37:30 -0500
From: George Georgalis <georgw@galis.org>
To: Eric Sandeen <sandeen@sgi.com>
Cc: linux-xfs@oss.sgi.com
Subject: Re: streaming media and realtime subvolume
Message-ID: <20021107173730.GB8321@trot>
References: <20021107151729.GA7085@trot> <1036683254.13907.4.camel@stout.americas.sgi.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1036683254.13907.4.camel@stout.americas.sgi.com>
User-Agent: Mutt/1.3.28i
Sender: linux-xfs-bounce@oss.sgi.com
Errors-to: linux-xfs-bounce@oss.sgi.com
Precedence: bulk

On Thu, Nov 07, 2002 at 09:34:14AM -0600, Eric Sandeen wrote:
>On Thu, 2002-11-07 at 09:17, George Georgalis wrote:

>> I've seen a few
>> mentions of the Linux xfs realtime subvolume but no doc, is it ready for
>> production? From what I can tell, it's a non journeled contiguous data
>> block. 
>
>The realtime volume is not supported, although it is basically
>functional.  You need to do an ioctl to the file to mark it realtime
>after it's created (but before any data is written to it) and then do
>Direct I/O to the file from then on.  The main difference is a more
>deterministic allocator that should allocate bigger chunks at a time. 
>"realtime" is perhaps a bit of a misnomer.  Oh, and it is journalled
>just as the main data volume is.

Can you give examples of 'direct i/o'? do you mean like dd? from which I
can pipe stdout to my media player?


> >Maybe I should just use ext2 for the media files? Would that be
>> higher performance? I'm not too worried about fsck, because in the case
>> of corruption I can remake the filesystem (data partition) and renew the
>> data from the node server.
>
>You'll probably just need to test in your environment, and see what
>works best.  Different filesystems excel at different things...

Yes, just trying to glean as much as I can before I spend time learning
things I don't need to know. :) Thanks for the tips.

// George


-- 
GEORGE GEORGALIS, System Admin/Architect    cell: 347-451-8229 
Security Services, Web, Mail,            mailto:george@galis.org 
File, Print, DB and DNS Servers.       http://www.galis.org/george