Re: Parallel databases?

James Lewis wrote:

> Does anyone have any suggestions for a way to keep 2 databases in sync?
>
> Ideally updates need to be made to both... this can't be too uncommon a
> requirement..... any kind of HA would need it....

No. The way HA works is that the system is made in such a way that you
can't lose data, or that you don't lose CPU cycles. HA does not make any
assumptions on the kind of applications that are running on the system.

If you want to experiment with HA, start with building a mirroring disk on
your Linux system to get the feel of it.

Then try to asses what you really want : low down-time or 7x24 operation.
This is what determines your HA system.

If you don't want to lose CPY cycles, then you have to build a cluster
with e.g. two CPU's. These should share their mass storage. This mass
storage should be organised as RAID. With hot-plug capabilities, it is
possible to keep the system running either if a CPU goes down or if a
drive fails.

The worst thing that you can do is to base the implementation of your
application upon the fact that the system should have high-availability
requirements. That is not a database issue, but an operating system issue.

Jurgen Defurne
defurnj(at)glo(dot)be