Hi Jeff.
On Fri, Sep 14, 2007 at 03:07:46PM -0400, Jeff Garzik (jeff@garzik.org) wrote:
:)
Yes, block device itself is not able to scale well, but it is the place
for redundancy, since filesystem will just fail if underlying device
does not work correctly and FS actually does not know about where it
should place redundancy bits - it might happen to be the same broken
disk, so I created a low-level device which distribute requests itself.
It is not allowed to mount it via multiple points, that is where
distributed filesystem must enter the show - multiple remote nodes
export its devices via network, each client gets address of the remote
node to work with, connect to it and process requests. All those bits
are already in the DST, next logical step is to connect it with
higher-layer filesystem.
Well, originally (about half a year ago) I started to draft a generic
filesystem which would be just superior to existing designs, not
overbloated like zfs, and just faster.
I do believe it can be implemented.
Further I added network capabilities (since what I saw that time
(AFS was proposed) I did not like - I'm not saying it is bad or
something like that at all, but I would implement things differently)
into design drafts.
When Chris Mason announced btrfs, I found that quite a few new ideas
are already implemented there, so I postponed project (although
direction of the developement of the btrfs seems to move to the zfs side
with some questionable imho points, so I think I can jump to the wagon
of new filesystems right now).
DST is low level for my (theoretical so far) filesystem (actually its
network part) like kevent was a low level system for network AIO (originally).
No matter what filesystem works with network it implements some kind
of logic completed in DST.
Sometimes it is very simple, sometimes a bit more complex, but
eventually it is a network entity with parts of stuff I put into DST.
Since I postponed the project (looking at btrfs and its results), I
completed DST as a standalone block device.
So, essentially, a filesystem with simple distributed facilities is on
(my) radar, but so far you are first who requested it :)
--
Evgeniy Polyakov
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