On Sat, Oct 11, 2008 at 01:07:44PM +0200, Danny Braniss wrote: > > On Sat, Oct 11, 2008 at 12:35:16PM +0200, Danny Braniss wrote: > > > > On Fri, 10 Oct 2008 08:42:49 -0700 > > > > Jeremy Chadwick <[EMAIL PROTECTED]> wrote: > > > > > > > > > On Fri, Oct 10, 2008 at 11:29:52AM -0400, Mike Meyer wrote: > > > > > > On Fri, 10 Oct 2008 07:41:11 -0700 > > > > > > Jeremy Chadwick <[EMAIL PROTECTED]> wrote: > > > > > > > > > > > > > On Fri, Oct 10, 2008 at 03:53:38PM +0300, Evren Yurtesen wrote: > > > > > > > > Mike Meyer wrote: > > > > > > > >> On Fri, 10 Oct 2008 02:34:28 +0300 > > > > > > > >> [EMAIL PROTECTED] wrote: > > > > > > > >> > > > > > > > >>> Quoting "Oliver Fromme" <[EMAIL PROTECTED]>: > > > > > > > >>> > > > > > > > >>>> These features are readily available right now on FreeBSD. > > > > > > > >>>> You don't have to code anything. > > > > > > > >>> Well with 2 downsides, > > > > > > > >> > > > > > > > >> Once you actually try and implement these solutions, you'll > > > > > > > >> see that > > > > > > > >> your "downsides" are largely figments of your imagination. > > > > > > > > > > > > > > > > So if it is my imagination, how can I actually convert UFS to > > > > > > > > ZFS > > > > > > > > easily? Everybody seems to say that this is easy and that is > > > > > > > > easy. > > > > > > > > > > > > > > It's not that easy. I really don't know why people are telling > > > > > > > you it > > > > > > > is. > > > > > > > > > > > > Maybe because it is? Of course, it *does* require a little prior > > > > > > planning, but anyone with more than a few months experience as a > > > > > > sysadmin should be able to deal with it without to much hassle. > > > > > > > > > > > > > Converting some filesystems are easier than others; /home (if you > > > > > > > create one) for example is generally easy: > > > > > > > > > > > > > > 1) ZFS fs is called foo/home, mounted as /mnt > > > > > > > 2) fstat, ensure nothing is using /home -- if something is, shut > > > > > > > it > > > > > > > down or kill it > > > > > > > 3) rsync or cpdup /home files to /mnt > > > > > > > 4) umount /home > > > > > > > 5) zfs set mountpoint=/home foo/home > > > > > > > 6) Restart said processes or daemons > > > > > > > > > > > > > > "See! It's like I said! EASY!" You can do this with /var as well. > > > > > > > > > > > > Yup. Of course, if you've done it that way, you're not thinking > > > > > > ahead, > > > > > > because: > > > > > > > > > > > > > Now try /usr. Hope you've got /rescue available, because once > > > > > > > /usr/lib > > > > > > > and /usr/libexec disappear, you're in trouble. Good luck doing > > > > > > > this in > > > > > > > multi-user, too. > > > > > > > > > > > > Oops. You F'ed up. If you'd done a little planning, you would have > > > > > > realized that / and /usr would be a bit of extra trouble, and > > > > > > planned > > > > > > accordingly. > > > > > > > > > > > > > And finally, the root fs. Whoever says "this is easy" is kidding > > > > > > > themselves; it's a pain. > > > > > > > > > > > > Um, no, it wasn't. Of course, I've been doing this long enough to > > > > > > have > > > > > > a system set up to make this kind of thing easy. My system disk is > > > > > > on > > > > > > a mirror, and I do system upgrades by breaking the mirror and > > > > > > upgrading one disk, making everything work, then putting the mirror > > > > > > back together. And moving to zfs on root is a lot like a system > > > > > > upgrade: > > > > > > > > > > > > 1) Break the mirror (mirrors actually, as I mirrored file systems). > > > > > > 2) Repartition the unused drive into /boot, swap & data > > > > > > 3) Build zfs & /boot according to the instructions on ZFSOnRoot > > > > > > wiki, just copying /boot and / at this point. > > > > > > 4) Boot the zfs disk in single user mode. > > > > > > 5) If 4 fails, boot back to the ufs disk so you're operational while > > > > > > you contemplate what went wrong, then repeat step 3. Otherwise, > > > > > > go > > > > > > on to step 6. > > > > > > 6) Create zfs file systems as appropriate (given that zfs file > > > > > > systems are cheap, and have lots of cool features that ufs > > > > > > file systems don't have, you probably want to create more than > > > > > > you had before, doing thing like putting SQL serves on their > > > > > > own file system with appropriate blocking, etc, but you'll want > > > > > > to > > > > > > have figured all this out before starting step 1). > > > > > > 7) Copy data from the ufs file systems to their new homes, > > > > > > not forgetting to take them out of /etc/fstab. > > > > > > 8) Reboot on the zfs disk. > > > > > > 9) Test until you're happy that everything is working properly, > > > > > > and be prepared to reboot on the ufs disk if something is > > > > > > broken. > > > > > > 10) Reformat the ufs disk to match the zfs one. Gmirror /boot, > > > > > > add the data partition to the zfs pool so it's mirrored, and > > > > > > you should have already been using swap. > > > > > > > > > > > > This is 10 steps to your "easy" 6, but two of the extra steps are > > > > > > testing you didn't include, and 1 of the steps is a failure recovery > > > > > > step that shouldn't be necessary. So - one more step than your easy > > > > > > process. > > > > > > > > > > Of course, the part you seem to be (intentionally?) forgetting: most > > > > > people are not using gmirror. There is no 2nd disk. They have one > > > > > disk > > > > > with a series of UFS2 filesystems, and they want to upgrade. That's > > > > > how > > > > > I read Evren's "how do I do this? You say it's easy..." comment, and I > > > > > think his viewpoint is very reasonable. > > > > > > > > Granted, most people don't think about system upgrades when they build > > > > a system, so they wind up having to do extra work. In particular, > > > > Evren is talking about spending thousands of dollars on proprietary > > > > software, not to mention the cost of the server that all this data is > > > > going to flow to, for a backup solution. Compared to that, the cost of > > > > a few spare disks and the work to install them are trivial. > > > > > > > > > > Yeah, this isn't something you do on a whim. On the other hand, it's > > > > > > not something that any competent sysadmin would consider a pain. > > > > > > For a > > > > > > good senior admin, it's a lot easier than doing an OS upgrade from > > > > > > source, which should be the next step up from trivial. > > > > > I guess you have a very different definition of "easy". :-) > > > > > > > > Given that mine is based on years of working with the kinds of backup > > > > solutions that Evren is asking for: ones that an enterprise deploys > > > > for backing up a data center, the answer may well be "yes". > > > > > > > > > The above procedure, in no way shape or form, will be classified as > > > > > "easy" by the user (or even junior sysadmin) community, I can assure > > > > > you > > > > > of that. > > > > > > > > I never said it would be easy for a user. Then again, your average > > > > user doesn't do backups, and wouldn't know a continuous backup > > > > solution from a credit default swap. We're not talking about ghosting > > > > a disk partition for a backup, we're talking about enterprise-level > > > > backup solutions for data centers. People deploying those kinds of > > > > solutions tend to have multiple senior sysadmins around. > > > > > > > > I wouldn't expect a junior admin to call it easy. At least, not the > > > > first two or three times. If they still have problems with it after > > > > that, they should find a new career path, as they aren't ever going to > > > > advance beyond junior. > > > > > > > > > I'll also throw this in the mix: the fact that we are *expecting* > > > > > users > > > > > to know how to do this is unreasonable. It's even *more* rude to > > > > > expect > > > > > > > > Um, is anyone expecting users to do this? I'm not. ZFS is still marked > > > > as "experimental" in FreeBSD. That means that, among other things, > > > > it's not really well-supported by the installer, etc. Nuts, as of > > > > January of this year, there wasn't an operating system on the planet > > > > that would install and boot from ZFS. > > > > > > > > I'm willing to jump through some hoops to get ZFS's advantages. Those > > > > happen to include some things that go a long way to solving Zefren's > > > > problems, so it was suggested as the basis for such (not by me, mind > > > > you). Having done the conversion, and found it easy, I responded when > > > > he asked how hard it was. > > > > > > > > But I'd never recommend this for your average user - which pretty much > > > > excludes anyone contemplating continuous backup solutions. > > > > > > > > > that mid-level or senior SAs have to do > > > > it "the hard way". Why? I'll > > > > > explain: > > > > > > > > > > I'm an SA of 16+ years. I'm quite familiar with PBR/MBR, general disk > > > > > partitioning, sectors vs. blocks, slices, filesystems, and whatever > > > > > else. You want me to do it by hand, say, with bsdlabel -e? Fine, I > > > > > will -- but I will not be happy about it. I have the knowledge, I > > > > > know how to do it, so why must the process continue to be a PITA and > > > > > waste my time? > > > > > > > > Did I ever mention bsdlabel? But in any case, ZFS makes pretty much > > > > *all* that crap obsolete. You still have to deal with getting a boot > > > > loader installed, but after that, you never have to worry about > > > > partitioning, blocks, sectors, or slices again - until you go to an > > > > operating system that doesn't have ZFS. > > > > > > so can Freebsd boot off a ZFS root? in stable? current? ... > > > > boot0 doesn't apply here; it cares about what's at sector 0 on the > > disk, not filesystems. > > > > boot2/loader does not speak ZFS -- this is why you need the /boot UFS2 > > partition. This is an annoyance. > > > > For the final "stage/step", vfs.root.mountfrom="zfs:mypool/root" in > > loader.conf will cause FreeBSD to mount the root filesystem from ZFS. > > This works fine. > > so the answer is: > yes, if you have only one disk. > no, if you have ZFS over many disks > > because I see no advantage in the springboard solution where ZFS is used to > cover several disks. > > I'm asking, because I want to deploy some zfs fileservers soon, and so > far the solution is either PXE boot, or keep one disk UFS (or boot off a USB) > Today's /(root+usr) is somewhere between .5 to 1Gb(kernel+debug+src), > and is readonly, so having 1 disk UFS seems to be a pitty.
Hold on a minute. "One disk" has nothing to do with the filesystem. You asked if FreeBSD could boot off of a specific filesystem, and I answered that -- I didn't state anything about disk counts. Now you're changing the focus. :-) I'm pretty sure FreeBSD can boot off of gmirror setups (see above, boot2/loader should work off of gmirror), which means >1 disk. You do not have to gmirror the entire disk, you can gmirror just a slice (AFAIK). I think (hope?) you can use the "remaining" (e.g. non-UFS/non-gmirror) part of the 2nd disk for ZFS as well, otherwise the space would go to waste. The "Root on ZFS configuration" FreeBSD ZFS Wiki page seems to imply you can. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB | _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
