[ENBD] Even more on 2GB Limits... Huh...

[Peter T. Breuer]

"A month of sundays ago Kai Chen wrote:"
> I'm positive about "merge_requests=0 + mount -o sync" making it work at last 
> (NBD 2.4.21 + Kernel 2.2.18).
> 
> >>Yes.  I do have LVM, and it is a patch for 2.2.18.  I just haven't run it 
> >>with NBD yet.
> >
> >Run it or applied it? Applying a patch is sufficient to alter your
> >kernel in many ways (if you compile it :-).
> 
> Well I did apply the patch and compile a new kernel with LVM support.  I 
> don't think it will present a problem for NBD, right?

I can't tell without looking at the patch. If the patch touches
ll_rw_blk.c or buffer.c or blkdev.c then it is possible that it
will.

> I checked the old archive, and I saw somebody was comparing DRBD with ENBD.  
> I think DRBD is somewhat like ENBD + "networked RAID 1."  Could you comment 

DRDB directs requests from a client to all of several servers and takes
the first to respond on read. I think. It's logically the same as raid1 over
several (E)NBDs.  I don't know how it does reintegration, or what the
communication channel is like (secure? redundant?).

> on that?  I plan to build an HA NBD cluster, and I intend to use ENBD.  I'd 
> like to learn your view on this issue.

I honestly can't say!

Peter