[Fwd: Data Replication questions]

This is a multi-part message in MIME format. --------------F724C528E02D3633733E7534 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit --------------F724C528E02D3633733E7534 Content-Type: message/rfc822 Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Mozilla-Status2: 00000000 Message-ID: <37484D39.E54C3140@starnet.com.eg> Date: Sun, 23 May 1999 21:47:21 +0300 From: Amgad Al-Sisi <amgad@starnet.com.eg> X-Mailer: Mozilla 4.51 [en] (Win95; I) X-Accept-Language: en MIME-Version: 1.0 To: Madison Pruet <mpruet@informix.com> Subject: Re: Data Replication questions References: <7i9eeh$h1k$1@nnrp1.deja.com> <374856D5.347C35A5@informix.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Dear Madison Pruet, Thanks a lot for your feedback. I have the following additional points for discussion: The hardware resources (the backup server and network bandwidth and connection) is one issue which is very important. Can we accomplish either of HDR or ER on the given configurations. What really concerns us is the size of the backup server's RAM. It is only 2/5 the size of the 5 machines altogether. If we use HDR (provided we can have enough hard disk chunks - currently the customer is using cooked files ) then can we run the 5 instances on the replicating machine safely. Another issue of great concern is, if a server fails, then do we get the same performance from the replicating machine, given that it acts now as one server and a replicating machine for the other 4 servers. Do we anticipate a network meltdown? The customer is a Hospital with huge amount of non-stop transactions Is it better to provide dedicated ethernet cards and cables between the 5 servers and the backup one. If we go with ER do you expect that we are immune from the above possible problems? or do we need to upgrade the backup-server (at least the RAM size)? One last point, can we use both mirroring and replications without getting into steep performance degradation problems. Best regards, Amgad Al-Sisi Madison Pruet wrote: > How do you want to replicate the instances? > > Do you want to use HDR? If so, then the database chunks must be in the > same location on the secondary as the primary. Can you do this without > running into conficts? In this case you will have to have 5 instances on > the replicating server. > > Do you want to use Enterprise Replication. If so, then you can have a > single instance which is acting as a target for all of the other servers. > However, you should not attempt this on 7.22. That was the first version > of the engine that supported ER and there have been a lot of bug fixes > since then. > > amgad@starnet.com.eg wrote: > > > Dear colleauges, > > > > Our customer has the following setup: > > > > 5 ICL TeamServer machines running DRS/NX unix and Informix-Online > > version 7.22.UC2. Each server is a uni-processor > > machine with 128MB of RAM, where a separate database resides. For > > example, on the first server there is the personal > > database, on the second server there is the accounting database, and so > > on. The application is written in 4GL and use > > distributed transactions on 5 databases running on the LAN connected 5 > > DRS/NX servers. > > > > For fault tolerance, the customer have another machine (number 6) which > > is ICL superserver dual processors with > > 256MB of RAM. The customer wishes to use replication to obtain high > > availability, as this site is 24x7 working place. > > The customer wants to know if the superserver with the current > > configuration can be used to work as the replica machine > > for all the five servers or not. and whether it is better to start one > > Informix-Online instance with 5 databases on the > > superserver, where each database is the replica of the other one on the > > TeamServer (e.g. personal on machine #1, > > accounting on machine #2, ..etc.). Or, it is neccessary to start 5 > > instances of Informix-Online where each instance > > handles one database. > > > > If the current configuration is not enough, what would be the desirable > > configuration for the server hardware. > > The current no of users is around 100 users, and the site operates 24 > > hours a day, seven days a week, and > > wants to use replication as a mechanism to avoid service outage. > > > > The current LAN configuration is all of the Servers (5 + 1) are > > connected on a coaxial 10MBPS ethernet network. > > The current system performance is good for the user, but when > > replication starts, is it going to degrade because > > of the network bandwidth or the current server condifuration? Please, > > take this issue into consideration when > > evaluating the available options. > > > > This is an urgent case and I will really appreciate your earliest > > response. > > > > Regards, > > > > Amgad Al-Sisi > > > > --== Sent via Deja.com http://www.deja.com/ ==-- > > ---Share what you know. Learn what you don't.--- --------------F724C528E02D3633733E7534--