vSphere 4.1 Advanced - why use fault tolerance when only supports 1 cpu per vm?

[billu]

I am implementing vSphere 4.1 Advanced across 3 ESX boxes ( Dell R710 servers with identical configuration ). My main goal is to virtualized about 8 production servers and most require more than 1 cpu. With Fault Tolerance's limited support of only 1 cpu per VM, I can't see how this will help me at all. FT is a fantastic idea and I would love to find some way of making it work, but need some help understanding what everyone is doing with that limitation.

Thanks in advance for your ideas and thoughts!

Bill

[NuggetGTR]

The truth is that it might not suit your environment, and with the limitation on 1vcpu there is not much you can do. there is alot of situations where you would use this but there is allot of situations you wont, like exchange... i wouldnt want to run exchange on a single cpu system so I will still have to stick with mscs to provide failover and fault tollerance.

but a web serving server might very well run fine with 1 cpu and if you company is relying on this to be up for client access then FT would work great, same with middle teir boxes FT could be used.

Im sure we will see the amount of cpus increased over time but for the time being it wont suit everyone.

[vmroyale]

Hello.

FT is still a relatively new feature and the 1 vCPU limit is somewhat restrictive, but for many workloads it is a great addition to have. Vendors that don't provide cluster-aware applications, or even in-house developed applications that have become mission critical can achieve uptime never before possible with very little added complexity. The bigger apps like SQL, Exchange, Domino etc have application clustering options and (in my opinion) are not really the target applications for this feature right now. There has been discussion of adding additional vCPU support in the future, but it is apparently a quite difficult process.

Good Luck!

[AntonVZhbankov]

FT is a great technology and what is really great - it does not need complicated configuration. Just one mouse click to enable.

1 vCPU limitation is not a marketing idea, it's just very technologically complicated to run even 1 vCPU FT VM.

What I personally see as main FT target: old applications that don't have application-level clustering. FT is not a universal answer, and some downtime for HA is acceptable for most cases.

1 vCPU is very powerful still. In my environment 95% of VMs can run on 1 vCPU, and most of 2 vCPU VMs have more than 1 vCPU just because of application vendor requirements.

---

MCSA, MCTS Hyper-V, VCP 3/4, VMware vExpert

http://blog.vadmin.ru

[AWo]

Even if I don't have FT I had a lot of FT hardware installation (Marathon Endurance & EverRun FT) in the past, also supporting one CPU at this time. And it did what it was made for ans there are requirements for this.

As most of the virtual machines run with 1 vCPU (and it is best practise to start with as less vCPU's as possible), at least in our environment, I don't see why FT should not be used. There might be cases where it really doesn't fit. However there are enough cases where it fits, even with one vCPU.

AWo

VCP 3 & 4

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[DannoXYZ]

Is it possible to have that 1 vCPU be allocated ALL of the host's CPU resources? If you've got a quad-core 2.0ghz host, can you have the VM's 1 vCPU be allocated 8ghz?

[AntonVZhbankov]

No. 1 vCPU = 1 core.

---

MCSA, MCTS Hyper-V, VCP 3/4, VMware vExpert

http://blog.vadmin.ru

[AWo]

1 vCPU might run on each core, but never at the same time. At a given point of time one vCPU runs on one core. But that core might change.

AWo

VCP 3 & 4

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