Date: Fri, 17 Feb 2012 17:10:13 -0800 From: Devin Teske <devin.teske@fisglobal.com> To: <freebsd-questions@freebsd.org> Subject: RE: One or Four? Message-ID: <021d01ccedda$11dc1070$35943150$@fisglobal.com> In-Reply-To: <4F3EF815.4070000@herveybayaustralia.com.au> References: <4F3ECF23.5000706@fisglobal.com> <20120217234623.cf7e169c.freebsd@edvax.de> <20120217225329.GB30014@gizmo.acns.msu.edu> <021101ccedc9$89445cf0$9bcd16d0$@fisglobal.com> <290E977C-E361-4C7D-8F1E-C1D6D03BAD63@mac.com> <021501ccedd1$ef4201d0$cdc60570$@fisglobal.com> <FF97816E-74EE-434C-BB04-A8F21C07AF10@mac.com> <4F3EF6EA.6070805@herveybayaustralia.com.au> <4F3EF815.4070000@herveybayaustralia.com.au>
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> -----Original Message----- > From: owner-freebsd-questions@freebsd.org [mailto:owner-freebsd- > questions@freebsd.org] On Behalf Of Da Rock > Sent: Friday, February 17, 2012 5:00 PM > To: freebsd-questions@freebsd.org > Subject: Re: One or Four? > > On 02/18/12 10:55, Da Rock wrote: > > On 02/18/12 10:40, Chuck Swiger wrote: > >> On Feb 17, 2012, at 4:11 PM, Devin Teske wrote: > >>>> However, for whatever reasons, the overwhelming majority of folks > >>>> using MacOS > >>>> X don't have problems using a single root partition, and while they > >>>> sometimes do > >>>> fill up their disks, that's a situation which they should be able > >>>> to recover from > >>>> without needing expert assistance. I don't recall having unusual > >>>> issues in running > >>>> a partition out of space under FreeBSD, either, or difficulty > >>>> fixing things > >>>> afterwards-- > >>> Recipe for disaster: > >>> > >>> 1. You have a cron-job that pulls down /etc/master.passwd daily > >>> 2. Your cron-job also runs pwd_mkdb after "SUP"ing down > >>> /etc/master.passwd > >> Yes, I agree that this is a recipe for disaster; the reasons not very > >> correlated to disk space, however. > >> > >> Even twenty years ago, handling this via YP/NIS or NetInfo would have > >> made more sense, and nowadays folks would be far more likely to use > >> LDAP as the network user database, instead of pushing system password > >> database changes via SUP or similar replication mechanism locally to > >> individual hosts. > >> > >>> 3. A program fills "/" > >>> 4. cron fires > >>> 5. pwd_mkdb can't generate databases because not enough room on > >>> filesystem > >>> 6. System can no longer be logged into > >> #5 does not imply #6: if pwd_mkdb can't build a temporary version to > >> /etc/pwd.db.tmp& /etc/spwd.db.tmp, it will exit with an error rather > >> than invoke rename(2) to replace the working version of the password > >> database with something that might be broken. > >> > >> To be very specific, I would expect one to get: > >> > >> "/: write failed, filesystem is full > >> pwd_mkdb: /etc/pwd.db to /etc/pwd.db.tmp: No space left on device" > >> > >>> 7. System is rebooted > >>> 8. Can't log in (not even as root) > >>> 9. Go into single-user mode > >>> 10. No space to work in > >>> > >>> Sure... you can call it an "edge-case," but it's pretty common and > >>> this is only > >>> one of a myriad of ways we can reproduce the problem of filling-up > >>> "/" to cause > >>> major headaches. > >> > >> I've never heard of such a thing happening to a real FreeBSD system > >> in the past decade or more. The closest match to the issue results > >> in a failure of adduser(8) or pw(8) to add new users, but existing > >> users continued to work fine. > > These are edge cases that _do_ happen - Linux (heaven forbid!) is > > reknown for the all /, and I've been unable to boot properly into it > > with a full disk. I had to use a live disk to rescue it which took > > hours thanks to the $%^&! lvm filesystem. > > > > Its just so easy to run a multi partition as opposed to an all /. And > > how much does it cost/hurt to do it (especially given the inordinately > > large hdd's these days)? Next to nix (pardon the pun :) ). The > > reduction in problems for new users should be an incentive as well. > > > > As for how quickly a disk can fill - I'm an expert :) I can fill a > > terabyte disk in a matter of hours with video and not notice. The > > transfers can be tricky to coordinate seeing as the disk fills faster > > than I can move the large files to another filesystem. > > > > And I haven't even mentioned some of the games that I'm sure a novice > > desktop user will use... > > > > You don't have to necessarily 'hose' the system to render it unusable. > > Just have some obscure program or service that requires something like > > a temp file or the like to stop it from working, and make it difficult > > to find whats wrong. > I forgot to mention that the probable reason you haven't heard of any > such problems on real FreeBSD _is_ because it doesn't use the all /, or > a qualified sysadmin is watching over it. > +1 And as ideal as it is to sit and hypothesize how great things might be in the Desktop world if Desktop users are given the chance to use one big "/" partition, I'm just terribly afraid (as you likewise point out) that the decision to make this the default was short-sighted to say the least. -- Devin _____________ The information contained in this message is proprietary and/or confidential. If you are not the intended recipient, please: (i) delete the message and all copies; (ii) do not disclose, distribute or use the message in any manner; and (iii) notify the sender immediately. In addition, please be aware that any message addressed to our domain is subject to archiving and review by persons other than the intended recipient. Thank you.
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