How many virtual machines per san array?

[NeoTitan]

Hi all,

i know this question is quite difficult, but more or less, how many virtual machines per san array is recommended? or how many virtual machines per hba?

Thanks in advance.

[AntonVZhbankov]

You can place as many VMs per LUN, datastore or array as disk speed suit your needs.

Technically you can place MANY VMs per datastore.

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VMware vExpert '2009

http://blog.vadmin.ru

[NeoTitan]

Hi Anton,

thank you for your answer.

With my question I mean if there is some reocommendation about number of virtual machines per hba approximately.

Many thanks

[depping]

you want the real answer? IT DEPENDS.

which array are we talking about?

dedicated array for virtualization?

how many hosts?

what kind of I/O?

In other words, no one will be able to give you an answer.

Duncan

VMware Communities User Moderator | VCP | VCDX

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[NeoTitan]

Hi depping,

thanks for your answer.

I know it depends, but one hba iSCSI (1 gigabit) or FC (4 gigabit), how many virtual machines (no high priority vms) could support whitout problem?

Thanks again

[AntonVZhbankov]

Many VMs or some VMs, or even just one VM. It all depends on load and loadtype.

1 Gbit approx. equals 100MB/s throughput, 4 Gbit - 400 MB/s. Bottleneck is usually not on interface/protocol level, bottleneck is array performance. In some cases you can achieve fantastic 3 MB/s throughput with huge number of small disk operations while iSCSI can give 100MB/s in theory.

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VMware vExpert '2009

http://blog.vadmin.ru

[Patrick_Daigle]

As was already stated, it depends.

While it does not specifically answer your question I believe the following article by Duncan Epping could help you develop your own methodology for figuring it out. It deals with determining the maximum number of VMs per VMFS volume by looking at queue depth, among other things: