Re: simple 2 machine failover configuration

Hi Pete (and all),

    Thanks for the info. I'm quite new to Oracle so I'm not sure what type of info is needed to make a good decision on this. I've included a bit more info below but if there is something critical I need to consider please tell me.

    We're creating a relatively small DB, maybe a total of 50,000 records. About 20,000 of those records will be quite small, less than 100 characters. The remaining 30,000 will be larger, possibly a few K bytes.

    The 20,000 group will be updated once per minute (we may be able to optimize this so it is not all 20,000 but for now I'll assume all 20k). The other 30k are updated much less frequently and should be no problem. All of these record updates (writing) will come from a few well-known clients.

    Now, what we need to for multiple diverse clients to access the DB querrying the above records. The frequency of these queries is much less well-defined but can be assumed to be at least a few thousand queries per minute.

    The end goal here is to make sure the the clients making the queries can always contact the DB transparently. For now we have two machines to handle this. If one goes down the other should be able to handle everything without the clients even knowing there was a failure (well, clients connected at the time of failure would know but that's ok). If this is particularly difficult, a small down-time is ok if it is on the order of 1 minute or so.

    Today we do not have the goal of improving DB performance by using 2 machines, we only are doing that for the fail-safe configuration. In the future we may want to improve performace by adding more machines. This is a consideration but not critical...yet.

In regards to your comments:

> 1, Replicate the database in its entirety using Advanced Replication -
may not
> be possible with throughput needs, you need to worry about conflict
resolution
> etc.

I'm not entirely familar with Advanced Replication but from what I know this should be possible on the data side of things. If this is done, however, how does the "backup" DB transparently take the primary's place in the case of a failure?

> 2. Use OPS if you have a clustered configuration - there may be issues
here
> with pinging, though this is lessened with 8.1 and cache fusion (in the
> read-write scenario anyway).

I'm not familar with OPS or cache fusion. Could you give me some more info on this?

> 3. Use cluster failover at the OS level. Script the restart of the
database
> on the second node.

I understand the OS level of this but how would the 2 machines maintain identical DBs? Using method 1 above?

> 4. Standby database - may not meet the needs, but in 8.1 you can open the
> standby database in query only mode.

How does the standby become the main one? How does it then handle the queries transparently? This may be a good solution but I don't know enough about it.

> There's not enough information in your post to advise you on the best one,
so
> investigate these a little further.
>
> HTH.
>
> Pete

Thanks for the info. Any further advice would be greatly appreciated.

--Rainer Received on Tue Jan 04 2000 - 19:11:43 CST