There's no correlation between what volume you IPL from, and what volume contains your root file system. You can IPL from any volume you want to, once you've run zipl/silo/zilo against it. You can have different versions of kernels on each of those boot volumes if you want. The only thing that relates the two is the "dasd=" and "root=" values you specify in your parmfile, and what's in /etc/fstab on that root file system. (You _do_ want to keep those in sync. It's possible to specify "root=/dev/dasdb1" and have "/dev/dasdc1 /" in /etc/fstab. Not something I recommend.)
Kernel upgrades do involve different versions of /lib/modules/`uname -r`. Those can be copied from system to system via tar and ssh, or just scp. Not really a big deal, since they will fall into a different directory name than what is there currently. Kernel upgrades that modify /dev are far more rare, usually when doing something like going from 2.2 to 2.4. Those usually involve upgrades of a whole lot more products, and you will probably want to replace a whole lot more than just a few bits here and there. So, not really relevant to this discussion. You could share /boot if you wanted to, as long as you were willing for all the guests that do that to have the exact same 'dasd=" and "root=" values in their parmfile. Having them separate and running zipl/silo/zilo on each system via ssh is not much more difficult. Mark Post -----Original Message----- From: Chet Norris [mailto:[EMAIL PROTECTED]] Sent: Thursday, February 20, 2003 3:09 PM To: [EMAIL PROTECTED] Subject: Re: R/O Linux guest? Mybe were talking RedHats to SuSe's or something. I don't understand why /boot (the target of zipl) can be separated from the load point (/) file structure and /etc can't be. USS seemed to make some sense in that the things that made the image unique could be split away from the base code. ie. /etc, /var, /dev (and /tmp) A kernel upgrade would modify /lib, /dev and /boot. To roll out the new kernel without applying it individually in each image I would have to copy a new "/" file structure and a new /boot file structure and then copy my original /etc back in over top of it. Right? --- "Post, Mark K" <[EMAIL PROTECTED]> wrote: > /lib is, and must be, part of the root file system (unless you're > willing to > play the games that I am not). I'm not going to replace my entire > root file > system just to upgrade a kernel. So, no problem. > > Mark Post > > -----Original Message----- > From: Hall, Ken (ECSS) [mailto:[EMAIL PROTECTED]] > Sent: Thursday, February 20, 2003 12:58 PM > To: [EMAIL PROTECTED] > Subject: Re: R/O Linux guest? > > > What about /lib (and particularly /lib/modules)? You can't just > switch > kernels without having the corresponding modules available. > > Not to mention /var, and all of the RPM database stuff. > > Splitting off /boot seems to be mainly a relic from the days when > Linux > wouldn't boot if the root filesystem was bigger than 500mb. (or > whatever) on > Intel boxen. I haven't seen a good reason to do it > for a long time. If it's too big, it's a waste of space, and if it's > too > small, you can't keep the multiple kernels you want there. > > > -----Original Message----- > > From: Post, Mark K [mailto:[EMAIL PROTECTED]] > > Sent: Thursday, February 20, 2003 12:13 PM > > To: [EMAIL PROTECTED] > > Subject: Re: [LINUX-390] R/O Linux guest? > > > > > > Having /boot separate allows you to decide which volume you > > want to IPL > > from. It also allows you to have multiple IPL volumes > > available. I also > > have a /boot1, /boot2.4, etc. /root is root's home directory > > and it forces > > me to be careful with how much junk I put there. If it were > > part of /, then > > I could conceivably fill it up by being careless. > > > > In my particular case, /usr, /opt, are shared read-only with > > other systems. > > > > I'm not sure what you mean by a kernel upgrade forcing me to > replace > > multiple minidisks. Most of the stuff that would need to be > > upgraded along > > with the kernel typically lives in /usr. > > > > Mark Post > > > > -----Original Message----- > > From: Chet Norris [mailto:[EMAIL PROTECTED]] > > Sent: Thursday, February 20, 2003 7:24 AM > > To: [EMAIL PROTECTED] > > Subject: Re: R/O Linux guest? > > > > > > Per the below (03/12/02) response, what devices are Read-Only and > > shared? It seems to me that only /usr and /usr/src could be. Then > why > > separate /root and /boot? I know you had a good reason, and I'm in > the > > process of re-mapping my file structures. Also, doesn't a kernel > > upgrade force you to roll out multiple minidisk replacements? > > Too bad we can't map it the same as USS with a separate /etc > > per image. > > > > From Archives Date: Tue, 12 Mar 2002 18:38:59 -0800 > > Mark Post wrote: > > >/boot, /var and /tmp do _not_ have to be on the root file system. > > >Mine aren't. Unless you play some games, /bin, /dev, /etc, /lib, > > >and /sbin have to be part of the root file system. Anything else > > >can be easily put on a different one. > > >~ > df > > >Filesystem 1k-blocks Used Available Use% Mounted on > > >/dev/dasdb1 52284 35868 13720 72% / > > >/dev/dasdc1 1062992 388560 620436 39% /tmp > > >/dev/dasdd1 1417324 1337424 7904 99% /usr > > >/dev/dasde1 111572 50520 55296 48% /var > > >/dev/dasdf1 104596 73036 26164 74% /opt > > >/dev/dasdg1 10432 1756 8140 18% /boot > > >/dev/dasdh1 52284 4936 44652 10% /root > > >/dev/dasdi1 24384 12912 10216 56% /home > > >/dev/dasdj1 921228 773876 100556 89% /usr/src > > > > Mark Post > > > > > > > > ===== > > Chet Norris > > Marriott International,Inc. > > > > __________________________________________________ > > Do you Yahoo!? > > Yahoo! Mail Plus - Powerful. Affordable. Sign up now. > > http://mailplus.yahoo.com > > ===== Chet Norris Marriott International,Inc. __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com