Date: Wed, 07 Oct 1998 06:47:11 -0700 From: Mike Smith <mike@smith.net.au> To: asami@cs.berkeley.edu (Satoshi Asami) Cc: current@FreeBSD.ORG Subject: Re: CDROM as system disk Message-ID: <199810071347.GAA03046@dingo.cdrom.com> In-Reply-To: Your message of "Tue, 06 Oct 1998 16:26:05 PDT." <199810062326.QAA07881@silvia.hip.berkeley.edu>
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> > I'm thinking about using CDROMs as boot (system) disks on our cluster. > This is because the internal (IDE) drives shipped with the PCs seem to > have an enormous failure rate (25% in 1 1/2 years) and it's also a > pain in the backside to replace them. (We have external (SCSI) disks > too but would like to avoid using them as anything other than swap and > logs for reasons that I will not go into here.) You want to discover that CDROM drives have a similar MTBF under constant use? They'd slower, have lower data density, and if anything, will fail more rapidly. > So, the question is: is there anyone out there using this kind of > setup? I've played with it off and on. You really don't want to do it for a production environment unless you never touch the system disk in normal operation. > Obviously lots of stuff (except /tmp and /var) has to be read-only, > and I could get rid of most of the boot-time warnings and errors with > the following patches (relative to -stable) to move motd and nologin > to /var/run: The basic issue is that you still need some writable storage, and as long as that's local, you still have local disks. > (Incidentally, nologin seems to belong to /var/run in all senses of the > word; does anyone know why it's in /etc at all?) Hysterical raisins. > What do you guys think? Am I totally off the mark? Definitely. You have a reliability problem that you need to address. To start with, you need to work out whether the problem is actually inherent in the disks you're using, or whether it's environmental. Then you need to follow through; if its environmental (eg. heat, humidity, etc.), fix it. If it really is the disks, consider using better disks. Plenty of systems up 24/7 have disks 5 years old or more. Consider using removable disk sleds and keeping some spares around. Dumping disks and going with CDROMs isn't going to help you reliability-wise at all, and it'll hurt you in lots of other ways. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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