Questions about geom-gate and RAID1/10 and CARP

[Michael Schuh]

> There are others, like lustre, gfs, polyserve, etc, however none of them
> work in FreeBSD at this point.  A few people (including myself) have
> started a project to port gfs to FreeBSD (gfs4fbsd project on
> sourceforge).
Oh i think this was a very good idea......i'm will watch this project.
another good thing was gpfs from IBM.......
>
>
>
> I'm wondering actually if you couldn't actually do this with NFS, and
> hacking some pieces together.  Haven't thought through it, but seems
> like maybe you could make the active writer an nfs server, that also
> mounts it's own nfs share rw, but the nfs sharing would be on a virtual
> interface, or at least the one that 'moves' with your failover.  The
> other machines would mount that nfs server's export ro, and when it
> fails over, the one taking over would have to run a script to begin
> serving that export rw to all, and it's own client would continue its
> connection but now on it's new virtual interface.  You'd also have to
> have the ggate stuff set up, so that it was mirroring the original
> 'master' disk, but when the failover occurred, you would quickly mount
> your local mirrored disk rw, ignoring the 'unclean' message, begin a
> background fsck, then start the nfs server on that mount point.  You
> would probably also have to fail the original drive in the mirror to
> effectively 'fence' that node from making disk changes at the same time
> the new master did.

Oh yes, this was also possible, but i would slunk around the script/cron-hell.
It wasn't really a hell, but a serious error source.....
my prior idea was to mount union two different mounted nfs-servers.....
like your suggestion, but here comes the next problem......unionfs....
and later the sync.......

I hope a good solution for real HA is around the corner....

michael