What's the difference between a proxy resource and using dependencies

[AnnuB]

What's the difference between a proxy resource and using dependencies? As an example, if I want 2 applications to share the same Virtual-IP, which option is better :-

1)put the Virtual-Ip in its own group and then use dependencies from the 2 application service groups

2)Or add a proxy resource in the 2 application service groups to the Virtual-Ip resource?

In general what's the best practice for sharing infrastructure resources like NIC/Virtual-IP/Mount/Voume?. I am still reading up, but can a basic resource like Virtual-IP or MOUNT be part of 2 service groups if both groups require the same?

Thanks,

Annu

[Venkata_Reddy_C]

Proxy resource is used for to monitor None (Operations=None) type of resources, like NIC. 

For virtual IP is of OnOff (Operations=OnOff) type resource, so you should not use Proxy, you should use dependencies.

Regards,

Venkat

[mikebounds · Accepted solution]

Generally for OnOff resources you use dependencies and for resources with "None" operations you use Proxy - let me explain further.

An IP has "OnOff" operations - you online it and offline it and a NIC has "None" operations - you don't online or offline it, but it it required to be there for your application to work, so VCS just monitors it.  A proxy just copies state of resource it is proxying - it does NOT offline or online the resource it is proxing so it is suitable  for NIC, but not IP.

Also if 2 applications share the same IP, then it is better to put the resources all into one service group and use resource dependencies to make both applications depend on the IP as both applications will move as one unit from one server to another as they cannot co-exist on different servers if there share the same IP.

Mike

[AnnuB]

Thanks Mike, now I understand Both applications cannot be put in one service group as they will/may run at different times, but same IP is used to access the server by clients. So I should create a separate group for the Virtual-IP and 2 service groups and add dependencies from the application groups to the Virtual-IP group? And similarly I think they will end up sharing the same mountpath. So I should repeat the same steps for the mount resources?

Thanks,

Annu

[mikebounds]

If the applications may not run at the same time, then you can put Mount and IPs in one service group and your 2 App in a service group each dependent on the Mount/IP group.  If both Apps normally start on the server, then you can put all the resources into one group and then you still have the option of manually offlining one (or both) of the application resources.

Mike