TAC support on VM's with changed resources

[Jabeltra]

Hello,

I have a customer just using ISE for TACACS.  They have another NAC solution for their other needs.  They would like to know if they can reduce some of the VM resources that are in the small VM, since they have a limited feature need from ISE, and still get TAC support.  They specifically asked about disk space ( reducing down to like 200GB ) , but were curious as well about RAM and CPU.   They had some TAC cases with ACS, and they want to make sure anything they do is still supported by TAC.  I wanted to see if there was an official word out there as to yes or no for TAC support.  I know the resources are there now for best practices.

Thanks,

Jason

[Francesco Molino]

Hi,

To answer your question in terms of TAC support:
I have experience with customers doing such things and when they call TAC, they're getting supported. Don't know if it's a standard rule.

Now, can you tell your customer has a standalone ISE or distributed environnement?

Now if it's just to decrease disk space from 600Go to 200Go, it will work until ISE will popup an error message related to disk space not available. 600Go is a recommended value but for Tacacs only it should be enough.

[Mohammed al Baqari]

Hi,

If it is a running ISE, they can't reduce the size because reducing it
require repartitioning linux which they don't have access to. If they just
reduce the size of the VM from the vcenter, it will corrupt.

The only way to do it is to build new custom VM with the required sizing
and install the ISO then restore a backup from old ISE to new one. This
should be supported by TAC. Or instead download the 200GB OVA which is
published by Cisco and this is safer.

[Francesco Molino]

Good point Mohammed to mention you can't downsize an existing server. My comment by decreasing can be misinterpreted. I was taking in general for vm provisionning

[Damien Miller · Accepted solution]

I've been getting TAC help for ISE problems for years. Most problems I engage TAC on are unrelated to performance. But when a problem is performance related in any way you can be certain TAC will ask that the resources be confirmed.

ISE does run on less resources that "standard" current ova's (3515/3595). At the end of the day it's quite resilient being built on red hat. The key is that the BU has certified deployment models on specific resources. 

The others already mentioned, you can't decrease disk space without a reinstall from the iso or a redeployment of the ova. 

At the end of the day TAC wants you to conform to the reservations set out in the templates. Will it run with less, yes, are you assuming the risk, yes, will you get support for most problems, yes. If a customer has issues allocating VM resources to ISE, consider the SNS appliances. 

[Jason Kunst · Accepted solution]

Also keep in mind, just because you’re only running TACACS and not radius or other services, ise is tested and supported at the recommended levels regardless if you have one or all of the features enabled. It’s a one size fit all approach and we don’t test various combinations for different scaling options