I know we've had this discussion before.. but.. I fail to understand why everyone seems to find LVM reliable for everything BUT /. I'm promised it will certainly fail - it's just a matter of time. Why?? Why does the reliability of LVM suddenly break down when you talk about a particular filesystem? I find it illogical.
The few times I've experienced issues with / being an LVM are the very same issues I have with any other filesystem under an LVM .. missing disks, changed uuids, etc. I'm not especially advocating using LVM for / - although I find it has some advantages. I'm just asking why it's reliability is so much in question. What is there about / that makes LVM 'sure to fail'? I say humbug to that.. (oh yeah - it's thanksgiving - time to get the turkey in the oven) Scott p.s. I'll say this -- if you do put / under an LVM - have a bootable Linux disk you use for recovery around that doesn't use LVM at all (avoid vg name conflicts). Or at least be prepared to boot the install kernel.. That's the only difference I see in using / under an LVM .. recovery may not be as simple.. but the concepts for correcting LVM issues are the same. On Thu, Nov 26, 2009 at 10:38 AM, Mark Post <mp...@novell.com> wrote: > >>> On 11/26/2009 at 11:58 AM, And Get Involved <sunny...@wcb.ab.ca> > wrote: > > We use sles10 on z/VM. And also use LVM. > > > > where we should put /boot and / ? > > how large for physical volume? Should put / into physical partition? > > Based on a number of years experience with midrange systems, adjusted > slightly for the mainframe, I prefer this style setup: > # df -h > > Filesystem Size Used Avail Use% Mounted on > /dev/dasda1 388M 119M 250M 33% / > /dev/vg1/home 97M 4.2M 88M 5% /home > /dev/vg1/opt 74M 21M 50M 30% /opt > /dev/vg1/srv 1.2G 1.1G 100M 92% /srv > /dev/vg1/tmp 291M 17M 260M 6% /tmp > /dev/vg1/usr 1.2G 915M 183M 84% /usr > /dev/vg1/var 245M 69M 164M 30% /var > > Some day, this is going to be the default proposal for the SLES installer. > I'm just not sure when it will get high enough on the priority list to get > developer time for a release. > > For mainframes, there is little to no advantage having /boot be on a > separate partition. The same is true of almost all modern midrange systems, > but it tends to persist there from habit/tradition. > > I do _not_ put / into an LV. I've had enough problems trying to recover > the system when something went wrong to keep punishing myself by doing that > again. Note that you _will_ have a problem some day, it is just a matter of > time. By having all the other file systems broken out of / I never have to > worry about resizing it. Except for the contents of /root, it just doesn't > grow, and I have complete control of what goes in /root. Unless things work > out "just so" I usually wind up with a decent amount of unused space in the > VG. This is a good thing to keep in reserve so that you can expand one or > another of the LVs. > > So, what I do is take my first 3390-x volume, and put two partitions on it. > The first is for /, and I make that about 500MB or so. You can decide how > big you want it for your systems. The second is for LVM as a PV. All other > DASD volumes I only put one partition on, and those are all for LVM PVs. > Note that I am not talking about application/data storage space here. This > is only for the operating system. The non-OS space comes from additional > DASD (or SCSI) and that goes into a separate VG from the OS. > > > Why? > > See above. > > > I remember on one red book said put /boot on /dasda with the size 512 MB. > > then the rest put into LVM. Can't find that book anymore. Is that right? > > 512MB for /boot is way too large for any practical purpose. If you're > going to put / into an LV, I would only make /boot around 50-100MB. But, as > I said, I wouldn't have / in an LV. > > > Mark Post > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or > visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
