Cluster filesystems

Fast access to disks shared between nodes

OCFS2
Oracle's cluster filesystem
Like ext3 on-disk, except:
Extent-based
64-bit inode numbers
Has its own distributed lock manager ("dlm")

GFS
Developed by Sistina, freed by Red Hat
Includes LVM extensions
Has its own distributed lock manager ("dlm")

Issues:
Avoiding duplication between cluster implementations
Deciding what parts need to be in the kernel