There's nothing like running out of paging space to bring an AIX system to its knees, but I hit an unexpected paging space limitation today when I was trying to restore from a mksysb backup. I didn't run out of paging space - I didn't get the chance! When I tried restoring from a mksysb backup, I couldn't get past the initial bosinst menus. I hit this error:
invalid logical volume data.
Can not continue.
To reboot the
system, press reset.
>>> 1 Continue with Install
In fact, the Continue with Install didn't continue because of this mysterious image.data error.
The file /image.data contains the list of logical volumes and file systems for the re-creation of the rootvg. In my case, the /image.data was created when I ran the mkdvd command, so I knew it was up to date. You can also create the image.data by running mkszfile, or by invoking mksysb with the -i flag.
My restore attempt failed because of something corrupted or missing from /image.data. What was it?
As it turned out, it was the default paging space - hd6 - which had gone missing. That was because I had created other paging spaces (paging00, paging01 etc.) in their own volume group some months ago, and then removed hd6 altogether.
Although you don't have to have a paging space in rootvg to run your system (pretty dumb if you try running without paging space at all, but your system should still boot and run), it looks like you do have to have a paging space in rootvg to restore your system from backup.
One of the benefits you get from reading this blog is that you can learn from my mistakes. Make sure you keep hd6 in rootvg!