Will older, slower, diskless / consumer nodes slow down a VSAN system ?

[srodenburg]

Hello,

We have a 6 identical VSAN cluster nodes contributing storage.
We also have two older machines (think generation Proliant G7) which are simply "large" and we thought about using those two to host low-performance, non important VM's, of which we have a lot off.

Question:  will those two older boxes, which are much slower than todays hardware, drag down the performance of the entire VSAN solution. Will the 6 modern, contributing nodes "feel" the presence of such older machines and slow everything down?

There is the best-practice of not using an unbalanced cluster but does that refer to contributing nodes only?  I understand that "consumer only" nodes basically just "sit there" but when part of the vSAN Cluster, will they have a negative impact? If so, why?

The network-connections will be 10 gig and identical to the 6 contributing nodes. It's just CPU performance which is slower.

We will use affinity / non-affinity rules to keep those "low performance" VM's on those two older machines.

Kind regards,

Steven

[zdickinson · Accepted solution]

Good morning, this is how I understand your configuration.  6 new nodes in a vSAN cluster contributing storage.  2 old nodes in a vSAN cluster not contributing storage.  I would not expect the 2 old nodes to affect performance.  Just my opinion, no way for me to offer proof.  Thank you, Zach.

[srodenburg]

Hello Zach,

Thank you for your reply.

Yes. We are planning to add 2 old ESXi servers (nodes) to the vSAN cluster which will not be contributing storage.

[Jasemccarty]

The older hosts will not be contributing to the Virtual SAN storage, only running virtual machines?

I can't see how they would slow down Virtual SAN.

Keep in mind, you'll still need to license those additional 2 hosts for Virtual SAN, regardless of whether they are presenting storage or not.