From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Masover Subject: Re: some testing questions Date: Tue, 15 Aug 2006 16:52:47 -0500 Message-ID: <44E2422F.8090708@slaphack.com> References: <44DCC20C.7020400@email.si> <200608141615.58185.vs@namesys.com> <20060815142140.GA4247@kruemel> <44E228B7.10505@namesys.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <44E228B7.10505@namesys.com> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Hans Reiser Cc: Ingo Bormuth , reiserfs-list@namesys.com Hans Reiser wrote: > Ingo Bormuth wrote: >> >> #df: >> /dev/hda8 6357768 3478716 2879052 55% /cache >> >> Before doing so, the partition was >90% full. > The performance difference between >90% full and 55% full will be large > on every filesystem. When we ship a repacker, that will be less true, > because we will have large chunks of unused space after the repacker runs. Not always true. For one, doesn't Reiser4 arbitrarily reserve 5%? For another, look at his results -- unless I'm wrong, that's 3-7% fragmentation. If I'm wrong, it's more like .03-.07%. And lastly, at a certain point, percentages aren't really that accurate. I've got a 350 or 400 gig partition which is 95% full, according to df (which if I was right about that 5%, it's more like 90% full) and that still leaves a solid 10-20 gigs free. I mean, yes, performance will eventually start to suffer, but how much time and activity will it take to fragment 20 gigs of free space, especially with lazy allocation?