Re: HAMMER Update - 28 June 2008

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

:With pseudo-fs hammer, will i be able to specify size for each pseudo 
:filesystem? Is this basically going to eliminate the need for disklabels? 
:That would be fantastic. ie. single real hammer filesystem, with a pseudo 
:filesystems for /usr, /home and friends and be able to shrink them/expand 
:them as needed. Will these pseudo file systems be specified in fstab like 
:normal, and able to mount/umount them as needed?
:
:Cheers,
:Petr

    It isn't that complex, at least not for the first release.  The
    pseudo-fs's are just special subdirectories within a normal HAMMER
    filesystem.  These subdirectories have special characteristics, such
    as having their own inode numbering space, that allows them to be
    used as mirroring targets.

    I did consider making pseudo-fs's formally mountable but it would
    be a real mess to do it.   You *can* in fact mount them separately
    using NULL mounts (mount_null).  In DragonFly null mounts are just as
    efficient as normal mounts, and can be specified in /etc/fstab after
    the main HAMMER mount.

    The pseudo-fs's use the same space management as the primary mount
    right now.  I am not tracking space use on a per-pseudo-fs basis.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>