SRM License question

[thomps01]

I have 3 x ESX hosts in my recovery site each with 4 CPU sockets (12 total). These all reside in the same cluster.

I have only purchased 8 SRM licenses as the resource requirements for the protected VM's is fairly low.

To ensure I'm within my license tollerance I am only presenting the replicated storage containing the protected VM's to 2 of the ESX hosts.

However, I see in the event log the following message:

"The SRM Feature SRM_PROTECTED_HOST is over allocated by 4 licenses"

So my question is: How does SRM know which ESX hosts to license within a cluster?

[depping · Accepted solution]

It doesn't, it assumes the whole cluster is used for SRM. By the way presenting replicated LUNs to only half of the cluster is not a best practice, and something I would never recommend because the results of an HA initiated restart is unpredictable.

Duncan

VMware Communities User Moderator | VCP | VCDX

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[thomps01]

Duncan,

Thanks for the quick response.

Whilst I fully understand the reasons it's not best practice around HA, lets supose I created another cluster which considered the overhead for HA purposes and had 4 ESX hosts dedicated to my replicated LUNs.

I'd still be in the same situation regarding license errors in the event log (not that this is the end of the world!!).

So, I only need 4 hosts to provide enough failover capacity for my protected VM's whilst also meeting the HA N+1 config I've set, but my license server is actually dishing out licenses for 10 ESX hosts in the DR datacenter. I don't want to buy SRM licenses for all 10 ESX hosts but it appears this will be the only way to supress the message.

Am I right or talking twaddle?

[depping]

you are right, and unfortunately it's a known issue. I wish we would be able to create "sub-clusters" / "pairs" to avoid issues like this.

Duncan

VMware Communities User Moderator | VCP | VCDX

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[thomps01]

Thanks Duncan

I'm happy to live with a few error messages, but it's cleared up my confusion.

BTW - Since I've got your attention, yellow-bricks has provided me with so many helpful hints over the last year, so thanks and keep it up!

[depping]

Thanks for the compliments!

Duncan

VMware Communities User Moderator | VCP | VCDX

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[jbone_hu]

Hi,

SRM is licensed by PRIMARY or production site protected ESX CPU socket quantity.

So it does not matter how many hosts are on the recovery site, UNLESS its a two-way active-active config, the DR site being a production environment also, expecting failover to the primary (A site).

[steve31783]

Hi Duncan.. I have the same issue described here, which is that my VC is the central mgmt point for ESX hosts throughout the US, but I only want to license hosts within a paritcular cluster (which Ive bought licenses for).

Will SRM "accidentally" license the wrong hosts?

Will these licenses errors affect my ability to failover VMs, or are these in fact just errors in the log?

[jbock]

steve31783,

Unilke vSphere, SRM does not assign an SRM license to a specific host. Rather, it considers the SRM licenses a pool of protected capacity. It periodically scans the protected environment to determine how many hosts (and therefore processors) are being used to run the protected VMs. If that quantity is greater than the purchased license quantity, SRM will raise the error mentioned above. There are also a couple of other times that SRM will check the license count, including when you're doing things like trying to additional VMs into a recovery plan.

By design, SRM will not prevent failover due to a license check (although if you've never had a valid license, you will of course have problems trying to use an eval copy to failover VMs). The EULA does of course require that you have the necessary number of licenses at all times, regardless of the product behavior regarding enforcing licensing.

Hope that helps,

Jon

[steve31783]

Thanks Jon, that makes me feel much more comfortable. I was concerned Id have some type of issue. Id have like to have purchasedmore licenses, but due to cost we decided to utilize two hosts worth of capacity for our critical VMs. It just happens that these 2 hosts are part of a bigger custer, and I didnt realize you couldnt assign the licenses directly to the 2 SRM hosts.

When you say "unlike vsphere" do you mean ESX/vsphere in general, or are you referring to the way vSphere/VC4.0 handles licensing in the new version of SRM (which I havent used yet) ?

Thanks again.. much appreciate.

[jbock]

I'm referring to how ESX licenses are allocated to ESX 4 hosts--you assign a license to a specific ESX 4 host from the vSphere Client. SRM licenses are allocated and counted in roughly the same way in both SRM 1.0 and SRM 4.0 (even though the license key management changed from flexlm to vCenter Server).

--Jon

[admin]

Just to clarify, SRM keeps track of the licenses itself and only counts Hosts which have a Protected Virtual Machine registered to it (SRM does not license the entire cluster unless every host in the cluster has a Protected VM registered to it)

Generally speaking, in order to be in full compliance, you need to have enough licenses to license the entire cluster. As an alternative, you may want to consider creating a smaller cluster to prevent HA/DRS from spreading your Protected VMs across more hosts than you have SRM Licenses.

Hope that helps,

Jason