Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcso!hpfcdj!kinsell From: kinsell@hpfcdj.HP.COM (Dave Kinsell) Newsgroups: comp.sys.hp Subject: Re: Disktab, newfs SCSI drives on HP9000/370 Message-ID: <17330005@hpfcdj.HP.COM> Date: 1 Oct 89 23:27:33 GMT References: <787@pmafire.UUCP> Organization: Hewlett Packard -- Fort Collins, CO Lines: 61 / hpfcdj:comp.sys.hp / dave@pmafire.UUCP (Dave Remien) / 9:53 am Sep 29, 1989 / >On my machine with two 7959S drives, I'm trying to split 24 megs of swap >space between the two disks, 12 megs a piece. The disktab entries follow. >(Stock HP). I think someone's been hacking your disktab. There's no 16MB entry shipped on 6.5 systems. >b. s0 (roughly) goes down by 1024 sectors per MB of swap. Since ns and nt are constants, you can't always decrease s0 by exactly 1024 and end up with a whole number for nc. >OK. I make a new entry for my two 7959S drives that I want to have 12 MB >of swap each like so: >hp7959S_12MB|HP7959S_12MB:\ > :12 MBytes swap:ns#16:nt#12:nc#1578:\ > :s0#303168:b0#8192:f0#1024:\ > :se#256:rm#3350: You don't have ns*nt*nc=s0. This isn't fatal, but it will waste a bit of space. >Then I turn newfs loose, and it *tells* me that its making a 310MB file >system on my drive. The kicker is from df: The use of 'Mb' by newfs is unfortunate. It really means 310 million bytes, as in 303168*1024=310444032. This is the total number of bytes being used by the file system, not the usable storage. There's a fair amount of overhead, primarily for inodes. When allocating swap space on the disc, you need to work in units of 2^20 bytes instead of 10^6 bytes, since the swap mechanism is dealing with physical RAM. >My question is, where did it (my extra 20MB or 30MB) go? What the heck >is going on??????? Is disktab as messed up as I think it is? Am I all >wet? Doing a newfs -i 16384 with the standard 7959S entry gives an additional 14 meg of available space. You would risk running out of inodes if you did this, if you have a large number of small files. Something like 4096 should be fairly safe. -Dave Kinsell kinsell@hpfcmb.HP.COM "This is not an official statement of the Hewlett Packard Company. In no way, shape, or form. They disavow all knowledge of my actions. In fact, they don't even know I spend Sunday afternoons typing this stuff."