RE: HDR and sqlhosts files (reposted)

I'll take a stab at it... 1. HDR uses the connection that you tell it to use in the command to start replication: onmode -d [primary|secondary] <dbserver_name>where <dbserver_name> is either the DBSERVERNAME or DBSERVERALIAS of the dbserver on the *remote* box. This same name, of course, must be in the first column of one of the lines in the *local* sqlhosts file. And the fourth column in that same line, of course, will point to the service port in /etc/services over which HDR will communicate. This must be a network (not shared memory) connection. 2. You can use one of the old connections, provided you've got all the right 'linkages' in the new setup, i.e., ONCONFIG <==> sqlhosts <==> /etc/services, and also provided that your old 7.30 instance is not still up and trying to use the same connection. 3. When you say, "use the same TCP connection" -- the same as what? The same as the old instance *was* using? No problem. The same as the old instance *is still* using? I wouldn't try it. The same as the clients are using? That's what we do, and have run into no issues. As far as using a different port for the HDR connections, there *may* be some performance benefit, but almost certainly so if the connection is physically separate, i.e., different network card. BTW, HDR communication is pretty constant with a normally active system -- even when there's no real db activity, there's still pinging back and forth. Don't know if HDR could communicate through a MaxConnect server... Heiko??? HTH, Paul Mosser -----Original Message----- From: Jonathan Leffler [mailto:jleffler@informix.com] Sent: Monday, October 30, 2000 2:27 PM To: Bogdan Neagu Cc: Informix NewsGroup Subject: Re: HDR and sqlhosts files (reposted) On Mon, 30 Oct 2000, Bogdan Neagu wrote: >Hi, Jonathan > >Would you mind helping me with this? I posted it in the newsgroup, but >nobody loves me there. I saw it there an hour or two ago, decided I didn't really know the answer (partly because most of it is at least as much to do with HDR as it is with sqlhosts), and skipped on because I'm catching up after most of a week out of the office. However, I'll pretend I know the answer, and copy the news group so anybody out there who knows more about it than I do can correct my erroneous comments. >Date: Mon, 30 Oct 2000 13:32:17 -0500 >From: Bogdan Neagu <bogdan.neagu@alcatel.com> >Newsgroups: comp.databases.informix >Subject: Help please (reposted) > >Hi all. > >We try to configure an IDS 9.21 FC2 on Solaris 7 with HDR. The clients >though are 32-bits, so we were told to use TCP connections, not shared >memory. Correct; FCx servers can't talk to UCx clients over shared memory, and UCx servers can't talk to FCx clients over shared memory. >For the previous version used (7.30), we were using shared memory, and >our sqlhosts on one of the servers looks like: > >inf_shm onipcshm server_1 some_name >inf_tlia ontlitcp server_1 infserv_sys >otherinf_tlia ontlitcp server_1 otherserv_sys >inf_tlib ontlitcp server_2 infserv_sys >otherinf_tlib ontlitcp server_2 otherserv_sys> >My questions are: >1. How does HDR know which connection to use for HDR if there are more > entries in the sqlhosts for the secondary server? I've no idea. I assume you identify the server you are replicating to, and you can specify any entry in the sqlhosts file that identifies the server. But I still don't know, which is why I did not respond. >2. Do we need to replace the shared memory connection with a new TCP > one, listening to a new port, or we can use the existing TCP > connection? AFAIK, you can use the existing TCP connection. You might decide to allocate a second connection as discussed below... >3. Are there any performance issues if we use the same TCP connection? The only one that springs to mind is ensuring that there are spare connections for the HDR to use. I don't know whether the HDR stuff connects once at system initialization and thereafter uses the connection in perpetuity (probable, but by no means guaranteed), or whether it connects more frequently. If it connects more frequently, you might decide to configure a second TCP connection with its own NET VP and only allow that to be used by HDR operations. Or you could consider MaxConnect... -- Yours, Jonathan Leffler (Jonathan.Leffler@Informix.com) #include <disclaimer.h> Guardian of DBD::Informix v1.00.PC1 -- http://www.perl.com/CPAN "I don't suffer from insanity; I enjoy every minute of it!"