From owner-freebsd-hackers  Tue Jan 14 09:46:17 1997
Return-Path: <owner-hackers>
Received: (from root@localhost)
          by freefall.freebsd.org (8.8.4/8.8.4) id JAA25714
          for hackers-outgoing; Tue, 14 Jan 1997 09:46:17 -0800 (PST)
Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211])
          by freefall.freebsd.org (8.8.4/8.8.4) with SMTP id JAA25707
          for <hackers@freebsd.org>; Tue, 14 Jan 1997 09:46:12 -0800 (PST)
Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id KAA29999; Tue, 14 Jan 1997 10:33:28 -0700
From: Terry Lambert <terry@lambert.org>
Message-Id: <199701141733.KAA29999@phaeton.artisoft.com>
Subject: Re: Cyclic filesystem (WAS: Re: truss, trace ??)
To: karpen@ocean.campus.luth.se (Mikael Karpberg)
Date: Tue, 14 Jan 1997 10:33:27 -0700 (MST)
Cc: brian@awfulhak.demon.co.uk, hackers@freebsd.org
In-Reply-To: <199701140207.DAA12321@ocean.campus.luth.se> from "Mikael Karpberg" at Jan 14, 97 03:07:05 am
X-Mailer: ELM [version 2.4 PL24]
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: owner-hackers@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

> I for one couldn't care less how good the implementation is. I would just
> like a nice efficient way of making any logfile max out at a certain size,
> plus minus a little. I think you could just say that when you filled one
> block (no matter what blocksize you run on the disk) and you need to
> add a new one to the file, just grab the first block, remove it from the
> front, clear it, append it to the end and start filling in data. Mininum
> cyclic filesize, two blocks. Always cut at full blocksizes.

[ ... ]

> So... would this be hard to do, if you did it in the not-so-perfect, but easy
> way I described?

1)	Make FS stacking work (good luck; I've been submitting patches
	on this one for years... lieterally).

2)	Once stacking works, hide the mechanics and attribution in the
	stacking layer.

Yes, this means copying the file back in itself on truncation, but
it would work.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.