Migration from 0.9.1betaX to 0.9.1beta8 --------------------------------------- Unfortunately this process requires updating the on-disk metadata using a supplied tool. If you follow these instructions carefully there should be no problems but please read them at least once before attempting an upgrade. If your system has its root filesystem on LVM then please also read the relevant notes below. During the upgrade process it is strictly necessary not to run any LVM commands, which change the LVM configuration. The upgrade procedure requires you to run the upgrade tool, and then upgrade the kernel and user-land tools to beta8. If your kernel has LVM compiled into it (ie. not as a module) this will require a system reboot. It will be helpful if you have the new LVM source tree and kernel built (but not installed) before you start the upgrade procedure. We strongly recommend that you take a full system backup and check your recovery strategies before attempting this upgrade. In the examples below it is assumed that your LVM sources are in /root/LVM/<version> and your Linux kernel sources are in /usr/src/linux. If these locations differ on your system then change the instructions accordingly. The pvversion tool ------------------ The pvversion tool provided in the package makes a minor change to the on-disk metadata on PVs and changes the version number. Prior to beta8 the version number of the metadata was 1, it is now 2. The change is small and will not affect data stored on the volumes. pvversion is a perl script and expects to find the perl interpreter in /usr/bin/perl (no additional modules are required), if your perl interpreter is in a different directory, eg /usr/local/bin/perl, then edit the first line of the file accordingly. The "old" LVM userland tools will only recognise PVs with version 1 metadata, and the new (beta8+) tools will only recognise PVs with version 2 metadata. The pvversion tool can also revert the version number back to 1 should you encounter difficulties. Note that the pvversion tool needs to have the "right" userland tools in the PATH to work correctly so if you are upgrading from beta7 to beta8 with the command "pvversion -2" then you should have the beta7 tools on your PATH. If you are downgrading from beta8 to beta7 then you should have the beta8 tools on your PATH. Remember that by default the tools are dynamically liked against liblvm so just changing PATH may not be enough, you should also change LD_LIBRARY_PATH or use make install to actually move the binaries into place on your system. The command line for pvversion is a simple -1 or -2 switch followed by a list of all the PVs on your system. eg. If you have 8 SCSI disks with a single partition on each as PVs, then the following command could be used to upgrade to version 2: # pvversion -2 /dev/sd[a-h]1 or, to downgrade a small IDE-based system: # pvversion -1 /dev/hda2 /dev/hdb1 /dev/hdb2 Upgrade with LVM as a module ---------------------------- 1. Close all LVs. eg umount all LVM filesystems. Do *NOT* vgchange -an or unload the LVM module If this is not possible don't worry - it just means you will have to reboot at step 7. 2. cd to the new LVM build directory # cd /root/LVM/0.9.1_beta8/tools 3. Run the conversion tool #./pvversion -2 <PVs> 4. If that command gave any errors then stop now and read the "troubleshooting" section. 5. Now unload LVM # vgchange -an # rmmod lvm-mod 6. Now install the new tools # make install 7. Install the new lvm-mod.o in your modules directory # cd /usr/src/linux # make modules_install # depmod -a (only needed for Linux 2.2) 8. Install the new LVM module or reboot # modprobe lvm-mod # vgscan (ignore any errors that say "ERROR: different structure size stored in /etc/lvmtab.d" ) # vgchange -ay 10.You may now re-mount your logical volumes. Upgrade with LVM compiled into the kernel ----------------------------------------- 1. Patch the kernel following INSTALL and PATCHES/README instructions. 2. cd to the new LVM build directory # cd /root/LVM/0.9.1_beta8/tools 3. Run the conversion tool #./pvversion -2 <PVs> 4. If that command gave any errors then stop now and read the "troubleshooting" section. 5. Now install the new tools # make install 6. Reboot with the new LVM kernel Make sure that your bootup sequence includes the vgscan command. Upgrade from 0.8 ---------------- To upgrade from LVM 0.8 to LVM 0.9.1beta8, follow exactly the same procedures outlined above with the following additional step once the upgrade has been completed: - For each Volume Group (VG) you have it is necessary to create a small LV and remove it again. This step will add UUIDs to the physical volumes that LVM 0.9 uses to identify them. eg: for a VG called "homevg" issue the following commands: # lvcreate -l1 -An -ntempvol homevg # lvremove -f -An /dev/homevg/tempvol Root on LVM ----------- Running root on LVM is currently a complicated thing to do and only to be attempted if you really know what you are doing. The upgrade procedure to beta8 is potentially hazardous so you should make doubly sure that your backups and recovery strategies are in place. In particular we recommend you have a bootable linux system (perhaps on CD or spare disk or partition) available with statically linked versions of *BOTH* your current LVM tools and the new ones. The instructions below include vague statements like "edit lilo.conf" - it is assumed that you know what you are doing here. If not then you really should not be running root on LVM ! Also if you are using another boot loader such as grub you should modify the instructions accordingly. Running with root on LVM usually requires you to start the system with an initial RAM disk (initrd), this procedure assumes that you are using an initrd created with the lvmcreate_initrd script. If this is not the case you should make sure you understand what the upgrade process involves and how your installation is affected and modify the below instructions as appropriate. The basic procedure is similar to that above for the "normal" root case with the additional step of creating a new initrd and some extra steps to try to keep the system recoverable in the case of a problem. In addition to the new LVM tools you should have a copy of your existing LVM tools built and ready to install because this procedure requires you to switch between them. 1. Close all LVs. eg umount all LVM filesystems. Do *NOT* vgchange -an or unload the LVM module 2. cd to the new LVM build directory # cd /root/LVM/0.9.1_beta8/tools 3. Install the new tools # make install 4. Install the new kernel or module into its target directory (do *NOT* load the new module into the kernel yet). How you do this depends on whether you are using a module, the kernel version you are using and where you keep your kernel sources. If you are using modules here you should make sure that the lvm-mod.o file is in the correct place for it to be collected by lvmcreate_initrd and placed into the initial RAM disk. You may also want to make a copy of the old lvm-mod.o module at this point so you don't lose it. 5. Create a new initrd. If your new kernel is same version as the old one then it is recommended that you rename the old initrd first (as they are named by kernel version) # lvmcreate_initrd 6. Edit /etc/lilo.conf to add a new entry for the new kernel and initrd and also reflect the new name of the old initrd file. 7. Re-run lilo to install the new boot block # /sbin/lilo 8. cd to the old LVM build directory # cd /root/LVM/0.9.1_beta7/tools 9. Install the old tools again # make install 10.cd to the new LVM build directory # cd /root/LVM/0.9.1_beta8/tools 11.Run the conversion tool # ./pvversion -2 <PVs> 12.If that command gave any errors then stop now and read the "troubleshooting" section. 13.Install the new tools # make install 14.Reboot with the new LVM kernel and initrd. Reverting to your old version ----------------------------- If the upgrade does not succeed then it is possible to downgrade the metadata version on disk using the pvversion command: # pvversion -1 <PVs> Note that you will need to have the beta8 tools installed to be able to do this. Once you have downgraded the metadata you must also install your old userland tools and old LVM kernel module (or static kernel). The procedure is essentially the reverse of that outlined above. Troubleshooting --------------- If you follow the instructions carefully then the upgrade should go smoothly, however there are a number of things that can go wrong. pvversion -- no physical volumes found/given You have not listed any PVs on the command line, or those that were listed are not valid LVM physical volumes. This could mean that the volumes listed are already at the version number required. Use the command "pvscan" to get a list of valid physical volumes. Note that pvscan can only list volumes that have the same version number as the rest of the installed tools. pvversion -- created dummy LV "/dev/vg/pvversionsda820" on empty PV "/dev/sda" pvversion detected an unused PV in your system. To complete the upgrade pversion needed to create an LV on the PV. Under normal circumstances this LV will be removed automatically after the upgrade. This message is quite normal. If the LV still exists after the upgrade then you can safely remove it. lvcreate -- ERROR "Device not configured" creating VGDA for "/dev/vg/vol" in kernel pvscan -- inactive PV "/dev/sda" of VG "vg" [1.95 GB / 1.95 GB free] I don't know what causes the above errors but I have seen them occur. To get around them # vgchange -an # rmmod lvm-mod # modprobe lvm-mod # vgscan # vgchange -ay vgscan Sees no VGs, pvscan sees no PVs This usually means that the installed tools does not match the on-disk metadata version. If your tools are beta8 then downgrade them, if the tools are earlier then upgrade them to beta8. The command "pvscan --version" will tell you the current version of the tools.