From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4999538E.7070705@proweb.co.uk> Date: Mon, 16 Feb 2009 11:52:46 +0000 From: matt User-Agent: Icedove 1.5.0.14eol (X11/20080724) MIME-Version: 1.0 To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [9fans] Regarding venti block size Topicbox-Message-UUID: a15e53f2-ead4-11e9-9d60-3106f5b1d025 anooop.anooop@gmail.com wrote: > Hello All, > > I want to store some big files on venti. size range around 200MB. Is > there any way to do this? > > This is what I get when I try to store files of size around 300KB : > "write: input too big: max block size is 57344" > > I was wondering may be if increase the block size in arena partition > this can be done. so I tried to format arena with block size 200M but > it gave the error below. > > "anoop@allatoona:/usr/local/plan9/bin$ venti/fmtarenas -a 3800M -b > 200M arenas0. /dev/sda6 & > [1] 32604 > anoop@allatoona:/usr/local/plan9/bin$ block size too large, max 65536" > why are you choosing such a big block size ? Blocks size and file size are related such that ceil(filesize / blocksize) = numberofblocks The larger the blocksize the less likely you are of coalescing any (or that's what my intuition says). Sure, there's a tradeoff but the research has been done already and < 64k blocks looks to have been found appropriate. If your file is 300Kb and your blocksize 200M then every distinct 300kB file will occupy 200Mb of actual disk. Also, 200Mb is not a big file!!