Path: utzoo!attcan!uunet!bu.edu!husc6!paperboy!meissner From: meissner@osf.org (Michael Meissner) Newsgroups: comp.unix.questions Subject: Re: Why partition disks? Message-ID: Date: 31 May 90 18:51:02 GMT References: <157@locke.water.ca.gov> Sender: news@OSF.ORG Organization: Open Software Foundation Lines: 38 In-reply-to: rfinch@caldwr.water.ca.gov's message of 30 May 90 21:50:55 GMT In article <157@locke.water.ca.gov> rfinch@caldwr.water.ca.gov (Ralph Finch) writes: | We are about to receive two 1.2GB SCSI drives (Wren 7s) :-) :-) . | These will be used mainly for data storage with some space for home | directories and public domain stuff. We are wondering how to | partition these things when they get here. Actually we would like 1 | partition per disk if it won't hurt anything. | | 1) Does partitioning affect performance (capacity and speed)? | | 2) Does partitioning affect fragmentation? Does one have to worry | about fragmentation with Unix, or SCSI, or ? There is some folklore that things placed in the middle of the disk will be accessed quicker than things placed on either end since the head is typically somewhere near the middle. Thus some system managers have placed absolutely critical partitions in the middle to deal with this (yes, I've done this in a previous life). I'm not sure it's worth it, unless you have some fixed size data base that accounts for 80% of your disk traffic (though of course it might be an ideal spot for /usr and/or swap). It is possible that fsck and/or the kernel on some UNIX ports can't deal with a 1.2G disk (which is why the original unix partitioned disks). If your system limits you to 16-bit inodes, you probably should partition the disk, since you are getting into the range that the system won't be able to allocate all of the available disk blocks (I forget where the cutoff value is). Also, cpio can only deal with 16-bit in binary mode or ~18 bits in decimal inodes. Fragmentation will always exist, but UNIX gives you no tools to deal with it (other than full dump and load). -- Michael Meissner email: meissner@osf.org phone: 617-621-8861 Open Software Foundation, 11 Cambridge Center, Cambridge, MA Catproof is an oxymoron, Childproof is nearly so