Yes, but if you use TAF (which connects to both), you ALREADY have it. If you use 3-d party (which do not know about multi node configuration), your VIP idea will break it at once.
> Yes, during a RAC configuration you have to be careful. But after it is configured, there shouldn't be many changes afterwards. To me using 0.0.0.0 for a listener-address is a strange way of doing it, because it is also a security risk.
Risk? Which risk? Do we have Oracle serevrs on public network, with additional interface which should not listen? It is myths.
But I saw a huge DBS'a headache because of this dumb 'listen on 1 interface only' configuration (and they end up in listening on 0.0.0.0, for stability purposes).
> To me the question remains: How do you handle tcp/ip-timeouts. I.e. even keepalives run in timeouts.
VirtualIP is SERVCIE INTERFACE. So it should switch to theworking node instantly, accept connections, and switch back ONLY when old node started everything (or at least started listener and web services - listener can care of the rest, forwarding connections to the liv instance if local one did not started yet).
So, I'd like to see in 'giveback' logs - crs started - css started - listener started - asm started - databse started ... - vip switched back.
Then I can always connect to listener @ VIP and have it working, or connect to EM on VIP and hacve WEB connection, etc. Where is timeout problem at all?
> > > The only _reliable_ method of connections is _connect to all nodes, and use keepalives in BOTH directions_. All other methods of failover or failure detections have many scenarios when they do not work at all (and it confirms by my tests). > > To me connecting to all possible nodes is not a smart solution. Suppose you have 8 nodes. Would you preconnect to all of them? What are the scenarios, when VIPs do not work at all?
// it was scenario for 'no VIP' case. Oracle HAVE such mode. So, why it is strange? Of course, you unlikely will connec to 8 nodes - but to 2 - 4 - why not? And it is for NO-VIP scenario. For VIP, it could be simple - connect ALWAYS to vip IP (whic is SINGLE for the cluster); - let then listener to forward you, if necessary for load balancing.
You can always configure 2 VIP's etc, but VIP is (in general case) property of the cluster, not of the host - so in my case of 'testrac11, testrac12', I should have IP of
testrac11 testrac12 testrac-VIP testrac-VIP-db2 *(if I want , for example) ...
(notice - VIP is not node specific so VIP name should never have any node number).
Example - PIX firewalls, BigIP load balancers, Cisco HSRP (yes, I have 2 ciscos and 2 HSRP addresses, because I want to switch 2 different services, bit it is stil NETWORK peoperty not NODE property), Linux cluster, Veritas Cluster. In all cases, VIP switches ONLY if all required services are ALREADY up (for Cisco - if Serial-1 is up, for example). Oracle's VIP is uniq by design and very strange in behavior.
> > Thanks > > Clemens > > --- Originalnachricht --- > > If VIP is used just to speed up switchover (as you describe), > > than of course > > it all is correct, but it is a very strange method to have > > such result (app. > > can just connect to both nodes and use one which response > > first). > > > > And it all require very careful configuration, because listener > > listens on > > 0.0.0.0 in most cases (and many DBA configure it by these way, > > for > > reliability). > > > > PS. You can have NIC failures, switch failure, and many other > > cases of > > failures in real world, so these VIP transitions are not very > > useful anyway. > > The only _reliable_ method of connections is _connect to all > > nodes, and use > > keepalives in BOTH directions_. All other methods of failover > > or failure > > detections have many scenarios when they do not work at all > > (and it confirms > > by my tests). > > > > > > > > -- -- Original Message -- -- > > From: <CLEMENS.BLEILE@(protected)> > > To: "Alexei_Roudnev" <Alexei_Roudnev@(protected)>; "Silviu > > Marin-Caea" > > <silviu_marin-caea@(protected)>; <suse-oracle@(protected)> > > Cc: <clemens.bleile@(protected)> > > Sent: Friday, February 10, 2006 2:56 AM > > Subject: AW: Re: Re: [suse-oracle] When should a VIP address > > move to other > > node? > > > > > > > > > > Hi Alexei, > > > > > > I think there is a misunderstanding here. A service shouldn't depend on a > > failed-over VIP. > > > > > > Let's take an example of a 2-node RAC: > > > > > > A node crashes and the VIP starts on the other node. CRS activates the > > services on the other node as well, but it registers them under > > the listener > > of the local VIP (ie the VIP of the surviving node). If a > > client connects to > > the VIP of the failed node it gets an error back immediately > > (ORA-12541 (See ORA-12541.ora-code.com) no > > listener) and tries to connect to the next VIP in the address-list > > of your > > tnsnames.ora and succeeds to connect. I.e. a VIP running on a > > different node > > than it should returns an error. The important thing is that > > it returns the > > error immediately and the client can handle it immediately > > (e.g. with TAF). > > > > > > If the second node comes back then services remain on the node which > > didn't crash (if you have configured the service > > "Preferred/Available"). > > When the VIP switches back you may have a short "unavailability" > > to connect > > to the service (only to connect, not already "connected" > > sessions). On my > > Laptop with vmware this was 12 seconds. In a real environment > > probably less. > > After the failed node finished to boot I relocated the services > > back. This > > was another "unavailability" of service of 1 second. I started > > a test on my > > Laptop with 1 node up and running. To bring the service on the > > "down node" > > up again resulted in an unavailability of service of 13 seconds > > to connect > > to the service. > > > > > > Could you please explain where your long wait times come from? > > > > > > My understanding is that VIPs are there only for NIC-failures (i.e. a node > > crash means also a NIC failure ;-)). If a NIC failes then the > > VIP starts on > > another node and returns errors immediately when trying to > > connect to Oracle > > using this VIP. > > > > > > Ciao > > > > > > Clemens > > > > > > > > > > > > >
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