Mine the Harvest

Tag: linux grub boot partition lvm evms

Resizing Default LVM Partitions and Moving /boot

by on Jan.23, 2010, under Linux

Standard Disclaimer: This article makes recommendations on using tools to modify your LVM configuration, your /boot partition, kernel and grub. Data corruption from a mangled LVM, or a (temporarily) unbootable system through a corrupted or mis-configured grub, etc. are entirely possible. I am not responsible for any of this. If you have a running system and break it by changing these things, please realize that I am not to blame, nor will I be able to help you fix things. And of course, making complicated changes on a production environment is not advised. However, if you need to migrate to a larger /boot partition the following may help you. If you are unfamiliar with partitioning, LVM and grub, please plan on having a least a few hours to work your way through this the first time. Also, have a Live CD and possibly the SuperGrub CD already available before hand. You may also want to practice on a virtual machine before trying this on a running server, etc. Installing Virtualbox and setting an a test VM takes only minutes and provides a superlative learning environment.

There is only so far you can get with a 69M /boot.

If you are like me, when you last installed your distro you likely decided to go with the proposed LVM layout. Hey, why not right? This way you can more easily change the sizes of your logical volumes, adding more to home, stealing some from that /whatever slice you just never really ended up using. Plus you can always add another physical drive later for juicy (or potentially disastrous, I’ve heard it both ways) multi-volume LVM expansion goodness.

Or perhaps you just said “yea, sure — whatever” on the partitioning steps.

Despite the best, or worst, planning you at times just need to fix what you are left with.

In my case, for some reason know to only God and the face on Mars, when I last installed Suse I accepted the offered LVM layout, and along with the the pathetic 69M /boot partition. Well, as you start to add some other kernels for Xen, the Suse default and desktop kernels, and if you want to keep any old versions of these, or compile your own, you very quickly realize what a mistake you made.

Now, fixing this is not superlatively difficult of course, but there are easy ways and hard ways.

The hard way involves manually shrinking the LVM Volume Group (vg) which also requires shrinking the Logical Volums (lv) which it contains, which of course requires shrinking the filesystems they contain. Oh the pain.

(continue reading…)

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