Date: Tue, 30 Apr 2002 16:41:53 -0400 From: utsl@quic.net To: Terry Lambert <tlambert2@mindspring.com> Cc: "Andrew P. Lentvorski" <bsder@allcaps.org>, freebsd-fs@freebsd.org Subject: Re: Non-standard root filesystems Message-ID: <20020430204153.GB3603@quic.net> In-Reply-To: <3CCEC7D5.D22356A0@mindspring.com> References: <20020429153020.Q16532-100000@mail.allcaps.org> <3CCEC7D5.D22356A0@mindspring.com>
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On Tue, Apr 30, 2002 at 09:35:33AM -0700, Terry Lambert wrote: > FreeBSD treats root mounts as "special", relative to all other > mounts. This is a design error, but overcoming it requires a > reorganization of the mount code that's not really politically > easy to accomplish, even though it's technically very easy. > > Some of the stuff Poul is doing right now will probably help > you in the future with assembing things like RAID-able > volumes in the future -- but not help you right now. Linux has a syscall (pivot_root) to swap the root with another mounted filesystem. It is occasionally quite useful, and I've been wondering about implementing it (or something similar) on FreeBSD. Possibly you can tell me why that wouldn't work, or would be a bad idea. > As far as software RAID is concerned: it's a bad idea, from a > performance perspective; I don't recommend it. Note that I'm > the person who did the original user space RAIDframe port to > FreeBSD in the mid 1990's, so I'm not just talking out my butt: > the amount of overhead for parity calculation and storage is > *considerable*, and makes RAID hardware a *much* better idea. I agree with you about the performance. Hardware RAID is faster, more reliable, uses less resources, etc. However, many people don't have the budget for it. In my case, I have production systems running Linux with software RAID. I would much rather run hardware RAID and FreeBSD, but I have no budget to buy SCSI RAID controllers. Switching to FreeBSD+Vinum would be a reasonable solution, but I can't mirror root, and that creates a political problem. I get, "If FreeBSD and Vinum will be better, how come you can't mirror the root filesystem?" ---Nathan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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