From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin C.Atkins To: 9fans@cse.psu.edu Subject: Re: [9fans] venti arenas Message-Id: <20030401084701.5c3f4bf5.martin@mca-ltd.com> In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Date: Tue, 1 Apr 2003 08:47:01 +0100 Topicbox-Message-UUID: 882e55e8-eacb-11e9-9e20-41e7f4b1d025 On Tue, 1 Apr 2003 07:34:18 +0100 nigel@9fs.org wrote: > Forgive me for being a venti newcomer... > > I've just read out an arena, which is about 20% full. > I was expecting the last 80% of the image to be null, > but it isn't. The last ~16k of the image contains some > data. If I pop it through strings, the name of the > arena appears amongst other less meaningful stuff. > > Is this data important, or an artifact? > > Hi Nigel, I thought (from the venti paper) that copies of the block headers were written to the end of each arena (starting from the end and working back). This gives more robustness, and speeds up rebuilding the index, though without trying it, I wonder how great the second benefit really is. (But maybe it's an example of where thought experiments don't match reality :-) Martin -- Martin C. Atkins martin@mca-ltd.com Mission Critical Applications Ltd, U.K. http://www.mca-ltd.com