On Thu, Nov 30, 2006 at 03:00:43PM -0500, I wrote: > On Tue, 2006-11-28 at 17:37 +0100, Stefan Seyfried wrote: > > > So it is a good idea to tell the engineer to do "mkswap" on the swap > > partition before putting the disk into the replacement hardware. > > Ugh, no it's not. You really want the UUID on the swap area to remain > the same. In response, on Thu, 2006-11-30 at 21:13 +0100, Stefan Seyfried wrote: > Well, but the system won't care because it won't resume? > Or am i missing something? And On Thu, 2006-11-30 at 15:42 -0500, Daniel Drake wrote: > Why? > > [not questioning your reasoning, this is coming from someone who knows > very little about swap structure and what the UUID is used for] You want to get rid of the resume metadata from it, but you don't want to create a new swap structure. Normally it's not a problem, but in some environments, such as with shared-storage like in a SAN[1], we need to be able to identify that a swap device is really the one we mean to be activating; the UUID is one of the best pieces of data we've got. So you don't want to start over with a new swap partition, you want to clear the resume data only. Granted, I think most distros, if not all, and all the standard tools totally muck up swap on shared storage right now[0]. But that's no reason to advocate such a bad habit. For FC/RHEL making this work right is at least on my TODO list for the relatively near future. [0] "swapon -a" activates everything it finds, and that's what most distros do during boot. If you can see other machines' swap devices, that's bad. [1] If you hate that example, another with the same problem is when you're running a virtual machine which has its own physical disk partitions, i.e. vmware with /dev/sdb as its disk. -- Peter
