<< February 15, 2005 >>
i am not the target market

from some web page it seemed debian/ubuntu had some awesome tool for creating initrds for mounting root over nfs with kernels that don't support nfsroot. see, we are trying to get our test clusters and customers to use the binary kernels we release instead of everyone building their own kernels, because building kernels is not easy. also, it makes sense that if one customer has some problem with our kernels that another customer may have that same problem.

but i don't ues these kernels at home, since i have / on nfs (it makes switching distros on nodes to test things a lot easier, although some things are more difficult). really the goal is to use lustre for /, but i am still taking baby steps here. and how hard could it be to have my initrd mount / from nfs?

so anyway, ubuntu had this tool and i figured it'd be easier to install it on a test node than to build rpms or whatever. the ubuntu install went fine, aside from the fact that it let me install without setting a root password or creating a user account (my user accounts are done with ldap), and that it overwrote my netbooting mbr with its own grubby grub.

fortunately, i have installed linux before so i have a usb flash drive that knows how to boot from the network so i can fix my mbr. unfortunately, the sles kernel i have hangs during boot with scsi errors if i leave the usb key in. so i have to wait for the nic to initialize and the kernel to start loading, but pull it out before too long. fortunately, udev takes about 5 minutes to start because it hammers my (k6 300) LDAP server, and is started before nscd. but that is for another day.

at some point here, before i fixed my mbr, my test box stopped booting from my usb drive. i don't know if it was editing a text file on it with my mac (the linux boxes all hang or crash when i put it in, i think, and my windows box stays turned off when i'm not playing starcraft) or ubuntu or the scsi errors, but booting to ubuntu (single user mode, of course, since i have no way to log in) and toggling the bootable flag on the partition off then on with fdisk fixed that.

eventually i got to a point where i wanted to try an initrd, but all i can get linux to do is panic:

RAMDISK: cramfs filesystem found at block 0 RAMDISK: Loading 1416 blocks [1 disk] into ram disk... done. Kernel panic: VFS: Unable to mount root fs on hda2

so i'm left wondering if i should just turn on nfsroot on our kernels; is there a good reason red hat and suse don't have it enabled? i hope it's something about fitting something on a floppy disk, so that i can make sure phil puts that next to the slide about petabytes of storage at gigabytes per second.

posted by jacob around February 15, 2005