Date: Wed, 24 Dec 1997 12:58:41 -0800 From: Studded <Studded@dal.net> To: freebsd-questions@freebsd.org Subject: New scsi disk config help please Message-ID: <34A17781.A47C076@dal.net>
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Greetings, First off let me say that if this subject is better treated on -scsi or -hardware feel free to follow up there. I'm on both lists, but I'm trying to break my cross-posting habit. :) Also, what I'm doing here might be more complicated than it needs to be, but please bear with me since this is my first real scsi disk, and I'm fairly excited. :) I am getting an IBM DCAS 34330 UW for Christmas (based on recommendations here, thanks). I currently run DOS, OS/2 and FreeBSD -Stable on a 1.6 gig WD Caviar IDE. I will be adding the 34330 to my adaptec 2940 UW which up to this point has been badly underutilized running my zip disk. My current configuration is roughly, 180 M for DOS, 700 M for FreeBSD, and the rest for OS/2. What I would like to do is split the 34330 2 ways, with 1/4 of it dedicated to OS/2, and 3/4 of it for FreeBSD. The IDE drive will then be partly DOS, partly OS/2, and I'd like to leave one partition on it for FreeBSD, either for /usr/obj or /usr/src, and maybe a little more FreeBSD space. To complicate matters slightly, at some point in the upcoming year I want to build myself a new system, and the scsi card and scsi disks will be going into it, and the current IDE HD will be dedicated to freebsd with the intention of making my current machine a server. Now, my quetions are as follows. 1. Does my plan sound reasonable? I've been following things on the lists here for a while now, and I think I've planned for the best possible use of the two disks, but this isn't really my area. 2. Which filesystem should go on the "slow" IDE disk, /usr/obj or /usr/src? And will the make world benefits of having those two filesystems on different disks be worth it when one of them is IDE? If it makes any difference, the IDE drive is alone on its bus, with a CD-ROM on the other bus. 3. Is it at all desirable/necessary to split slices on a hard disk on physical platter boundaries? And if so, how do I determine where the divisions should be? The DCAS spec says it has 4 platters, which is one reason for me wanting to split the disk 1/4 and 3/4 above. It so happens that this also fits my needs. Disk labelling in FreeBSD is still pretty greek to me, so if you can help with this I need details. :) 4. Rather than blow away the last few months of work in the freebsd installation I have, I was thinking of installing freebsd all new on the scsi disk, then moving parts from the old installation to the new one. I have OS/2's Boot Manager on the IDE disk, and that's going to stay as is. I'm thinking the easiest way to get FreeBSD on the scsi disk is to install the scsi disk, slice it under the old freebsd install, remove the ide disk, and install FreeBSD on the scsi disk as if it's the only disk in the system. Then I can re-install the IDE disk and whack Boot Manager into shape. Does this sound reasonable? 5. If I'm understanding things correctly, FreeBSD's UFS is using a 4k inode size. Has anyone done any studies on whether this is optimal or not? I know from my OS/2 experience that the formula for optimal inode size is related to average file size, adjusted for anomalies in the distribution curve. For instance, every 512 byte directory entry wastes 3.5k of its inode on a 4k inode system. OS/2 has used 512 byte "inodes" in its HPFS system for years, and I'm wondering if the cost to UFS of managing the higher number of inodes would be worth the disk space savings. The wastage with 4k inodes averages out (in an ideal world) to 2k per file. This is much less significant on a 3+ gig slice, but for example I couldn't put the ports collection on my 96 M zip disk till I newfs'ed it with a smaller inode size. Any comments/suggestions welcome. :) 6. When I install FreeBSD on the scsi disk, any suggestions on sizes of the partitions? Obviously I won't have to worry too much about space, but I'd prefer not to waste any if possible. I want to install the linuxulator, and just about everything else. :) Anything else I should be thinking of? I would really like to get this right the first time, so I am very open to suggestions. Any help will be greatly appreciated. Happy holidays, Doug
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