Date: Thu, 21 Sep 2000 23:55:58 -0700 From: jdb-lists-freebsd-hackers@layer8.net To: hackers@freebsd.org Subject: Re: Frustration with SCSI system Message-ID: <20000922070129.2351937B423@hub.freebsd.org> In-Reply-To: Your message of "Thu, 21 Sep 2000 18:24:05 CDT." <20000921182405.A82919@staff.texas.net>
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> Ideally, I would use one of the IDE flash-based drives on the market. One > brand is SanDisk, and they take a standard IDE connector and fit into a > 3.5" drive bay. You can get them very reasonably priced up to 128MB or > so, which is just fine for a boot partition. Since flash drives have no > moving parts, mechanical failure is not an issue, and since the root > partition is not written to much, the flash will not wear out for a > long time (flash cells wear out after about 100,000 writes; the flash > drives do load balancing and stuff to ensure that the (many) cells in > the drive are written to evenly). I would suggest just not writing them at all if you can avoid it. They seem to need (and are spec'd for) about 500ms of power after a write which isn't feasible with some power-off situations. I've had them occasionally behave worse and develop "bad" sectors under what i thought to be normal operating conditions (meaning, I thought I satisfied the above limitation). The bright side is that reclaiming "bad" sectors is just rewriting them, but if that's in the middle of something useful, like an inode for something in /lib, your superblock, the data portion of /etc/passwd, etc., you're in uncomfortable shape. I would definitely advocate (and actively use them for) completely readonly disks, either by running completely readonly straight from the SanDisk or by keeping a (compressed?) readonly filesystem on the disk, booting readonly into a bootstrap environment, and copying or expanding a read/write root disk into a memory-based disk device (MD, MFS), and calling that your / partition. it's admittedly a rather klunky solution for a general purpose install. It also makes putting /etc on non-volatile media difficult, but it is still workable with a bit of ingenuity, or maybe by using a small bootstrap /etc which is remounted with a stable vinum partition (I haven't actually tried this; implementation is left as an exercise for the reader). Another consideration is that they have slow write performance relative to typical IDE or (especially) memory-based media. - joel > > Doug > > On Thu, Sep 21, 2000 at 03:29:17PM -0700, Keith Kemp wrote: > > On the topic of Vinum, what do you guys do about the / partion since it > > appears that a vinum partion can not be the boot partion. > > > > I would hate to have the drive with my boot partion fail and be left with a > > non working server. > > > > Keith Kemp > > > > > -----Original Message----- > > > From: owner-freebsd-isp@FreeBSD.ORG > > > [mailto:owner-freebsd-isp@FreeBSD.ORG]On Behalf Of Alfred Perlstein > > > Sent: Wednesday, September 20, 2000 12:51 PM > > > To: Edward Elhauge > > > Cc: freebsd-hackers@FreeBSD.ORG; freebsd-isp@FreeBSD.ORG > > > Subject: Re: Frustration with SCSI system > > > > > > > > > * Edward Elhauge <ee@uncanny.net> [000920 12:48] wrote: > > > > Hello Freebsders, > > > > > > > > I've been using FreeBSD over the last 6 years (since I switched from > > > > NetBSD) to run a small ISP out of my basement. > > > > > > > > I've had about six disk crashes in as many years and still > > > don't know how > > > > to work reliably with them. > > > > > > "man vinum" > > > > > > software mirroring == good. > > > > > > :) > > > > > > -Alfred > > > > > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > > > with "unsubscribe freebsd-isp" in the body of the message > > > > > > > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > > with "unsubscribe freebsd-hackers" in the body of the message > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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