Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site ulysses.UUCP Path: utzoo!linus!gatech!ulysses!smb From: smb@ulysses.UUCP (Steven Bellovin) Newsgroups: net.unix-wizards Subject: Re: Fast Filesystem defaults Message-ID: <1042@ulysses.UUCP> Date: Mon, 12-Aug-85 15:34:40 EDT Article-I.D.: ulysses.1042 Posted: Mon Aug 12 15:34:40 1985 Date-Received: Wed, 14-Aug-85 00:27:27 EDT References: <597@brl-tgr.ARPA> <1183@umcp-cs.UUCP> <1040@ulysses.UUCP> <1194@umcp-cs.UUCP> Organization: AT&T Bell Laboratories, Murray Hill Lines: 20 > >On rp07s, it's quite easy to run out of i-nodes; there are *many* blocks per > >cylinder group, and 2K i-nodes just doesn't make it. We have to override > >the cylinder group size on our rp07s just to get enough i-nodes. > > I don't quite understand.... From man 8 newfs: > > .B \-i number of bytes per inode > This specifies the density of inodes in the file system. > The default is to create an inode for each 2048 bytes of data space. > If fewer inodes are desired, a larger number should be used; > to create more inodes a smaller number should be given. > > If you have one inode per 2K of data space, then it doesn't matter > how many blocks/cyl-group; more blocks just means more inodes. So > how does having rp07s make any difference? Sorry, I wasn't explicit enough. There is a hard limit (MAXIPG) on the number of inodes per cylinder group; on rp07s, the default cylinder group is so large that newfs (I believe) *silently* cuts back on the i-node density, in order to stay within this limit.