On Thu, Feb 02, 2006 at 05:44:54AM -0500, Daniel Ouellet wrote:
> Ray Lai wrote:
> >On Wed, Feb 01, 2006 at 11:37:19PM -0500, Daniel Ouellet wrote:
> ><snip>
> >>This way, continuous live mirroring can be done and no need for cronjob,
> >>etc. And this would be much more efficient as well.
> ><snip>
> >
> >https://marc.theaimsgroup.com/?l=openbsd-misc&m=111186187916316
> >https://marc.theaimsgroup.com/?l=openbsd-misc&m=105358689405500
> >
>
> Thanks for this! It is rather interesting for sure, but still not fully
> provide what I would like to do and I am not sure of the following as well.
>
> - Mirroring on multiple servers, more then 2. Man page said you need an
> even amount of devices, fair, but all I read look like indicate it would
> mirror a to b and that's it, even if a could be maid of multiples drives
> if you like, so two copy is the limit.
I'm fairly certain you can run a ccd over a ccd. Or, better, raid over
vnd.
> - On servers reboot, (master or slaves) unknown stage after restart and
> I am not sure you could consider the data proper here. The only way I
> guess would be to destroy the ccd, recreate it and put the data back,
> but then, very long down time.
See the above raid comment.
> - Now on remote server, the point is to be able to use the data locally.
> Master -> slaves. Meaning multiple slaves where the source is one, live
> mirroring on multiple slaves and usage of local data to be served
> locally from there own local copy of the mirror. If I understand this
> properly, I am not sure you possibly mount that file part of the ccd
> device from the master on the local (slave server) and use the data as
> normal. I would say no.
>
> I am not saying this is a bad idea to use ccd, but reading for the last
> few hours on it, I am not sure it would fit the needs. But I sure could
> be wrong.
>
> Been able to add more mirrors at will is a plus and have each mirror be
> a simple OpenBSD setup for reliability is important.
>
> Plus looks like all would need to be done via nfs and if I could avoid
> it, I would prefer that for security reason. I much prefer using ssh for
> all communications between servers. But again, may be I overlook nfs as
> the last time I used it, was many years ago for these same reasons.
In the worst case, create an IPsec mesh (i.e., one connection per
server). It will take care of quite a few issues.
That being said, I don't think there is a really good solution to what
you want to do. drbd looked promising, some time ago, but is
Linux-only...
Joachim
