Path: utzoo!attcan!uunet!cs.utexas.edu!uwm.edu!psuvax1!psuvm!cunyvm!ndsuvm1!mtus5!bacon From: BACON@MTUS5.BITNET (Jeffery Bacon) Newsgroups: comp.unix.questions Subject: Re: the 10% factor Message-ID: <89323.004057BACON@MTUS5.BITNET> Date: 19 Nov 89 05:40:57 GMT References: <21436@adm.BRL.MIL> <2643@auspex.auspex.com> Organization: Computing Technology Services, Michigan Technological Univ. Lines: 43 In article <2643@auspex.auspex.com>, hitz@auspex.auspex.com (Dave Hitz) says: > >The problem is that as a file grows on a mostly full partition, the >block immediately following the last one in the file is generally not >available. Even on almost empty files this is always a possibility, >but statistically it turns out that only as the filesystem passes 90% >full does this problem become nasty. > How does one learn this stuff? I RTF(Sun)Ms, but it didn't help that much. Or was I looking in the wrong place? > >Now the question about swap is interesting. When you create a swap >file using mkfile(8), it allocates disk blocks when the file is >created. If you create a 20 MB swap file in an otherwise empty 20 MB >partition, the block allocation would probably be quite good because >there would be no conflict with smaller chuncks of space being >allocated in other files. If you want more than one swap file per partition, >that would probably work also, but make sure *not* to run the mkswap's in >parallel. Do them one after the other. (And don't use the -n option which >would defeat the whole point of getting the blocks nicely allocated at >create time.) > Well, I hate to sound too stupid, but I did just this on a couple of swap partitions I made a couple of months ago. (Run the mkfile(8)s in parallel. This is on a Sun 3/260, SunOS4.0.3, 2 280MB Fujitsu's, 3 ~36Mb swaps on two 117MB partitions. The partitions are packed full, with about 500K free each.) Should I remake the swap files? At the same time, it occured to me to cut the number of inodes and the size of the minfree value. After all, there are only 3 files...(plus the . and .. directory)...I don't see anything wrong with having done that, am I correct? >-- >Dave Hitz home: 408-739-7116 >UUCP: {uunet,mips,sun,bridge2}!auspex!hitz work: 408-492-0900 ------- Jeffery Bacon Computing Technology Svcs., Michigan Technological University bitnet: bacon@mtus5 uucp (alternate): !itivax!anet!bacos