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List:       veritas-ha
Subject:    RE: [Veritas-ha] Interplay between dependencies, failover and startup/shutdown
From:       "Tom Stephens" <tom_stephens () symantec ! com>
Date:       2006-02-28 22:55:58
Message-ID: 39310EC65ADF75458980739A2810901E02044320 () svlxchcln2 ! enterprise ! veritas ! com
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Sean,

	A few things here...  First, the sim is not 100% like the real
cluster.  In this case the proxy resource is treated just like another
resource, and not a mirror image of the TargetResName (how the proxy
actually works on a real cluster).
	Second, you could change your proxy def to:

Proxy Proxy_backup (
 		Critical = 0
 		TargetResName = backup_NicGroup
		)

	Tom


-----Original Message-----
From: veritas-ha-admin@mailman.eng.auburn.edu
[mailto:veritas-ha-admin@mailman.eng.auburn.edu] On Behalf Of Sean
Clarke
Sent: Tuesday, February 28, 2006 12:01 PM
To: veritas-ha@mailman.eng.auburn.edu
Subject: [Veritas-ha] Interplay between dependencies, failover and
startup/shutdown

 Hi All,
 
 Let me first apologise if the questions that I am asking are 
 stupid but I'm fairly new to VCS and what I do know I taught myself.
 
 We have a two node active-passive cluster running Oracle. I 
 am in the process of adding a new virtual IP to use for RMAN 
 backups via Netbackup.
 
 I am in the process of testing my proposed config using the 
 VCS simulator (which is great BTW).
 
 So my first step was to add a new NIC into the NicGroup SG
 
 NIC backup_NicGroup (
 		Device = qfe1
 		NetworkType = ether
 		)
 
 Then I added a Proxy to my Oracle service group
 
 Proxy Proxy_backup (
 		Critical = 0
 		TargetResName @node1 = backup_NicGroup
 		TargetResName @node2 = backup_NicGroup
 		)
 
 And finally I added an IP that depends on this proxy
 
 IP IPbackup_192_168_243_94 (
 		Critical = 0
 		Device = qfe1
 		Address = "192.168.243.94"
 		NetMask = "255.255.255.248"
 		)
 
 Made them all non-critical as I didn't want the application 
 failing over just because I can't run a backup :-) 
 
 This looks a bit like the diagram below
 

 
 		|IP_backup
             |
 Oracle SG	|     |
 		|	|
 		| Proxy_Backup (target NIC_Backup)
             |
 
 
 
 
 NicGroup SG  |
             | 
             |  NIC_Backup
 
 
 So as a test I told the Simulator to fault the NIC_Backup 
 resource, I expected Proxy_Backup to also be faulted (as that 
 was the target for the proxy)  and then the IP resource to be 
 faulted as it depends on the Proxy but no, Proxy_Backup 
 stayed looking fine.
 
 Now from reading some Docs it looks like the dependencies are 
 used to decide which order things start up in but failures 
 aren't propagated along them ie if resource A faults the 
 resource B doesn't automatically fault just because B depends 
 on A but at startup/failover A will always be started before 
 B and vice versa at shutdown/failover.
 
 I can believe this but how about the proxy -  I thought that 
 a proxy was meant to reflect the state of the real resource 
 so surely it should fault if it's TargetResName faults?
 
 Any enlightenment would be gratefully received :-)
 
 Thanks!
 
 Sean
            
 
 


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