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hypervisor servers

margo

Newbie
Joined
Apr 22, 2020
Messages
3
If An organisation has two hypervisor servers, each with the following specifications:

64GB RAM

2TB LUN attached via iSCSI

Intel Xeon 4110 8 core/16 thread CPU

They want to virtualise 30 Windows 2016 servers, 150 Debian servers and a FreeNAS file server.

The FreeNAS server would also be allocated a separate 64TB LUN via iSCSI to share with the network as NAS storage.

Do you think that their current server infrastructure can handle the load?

What specific requirements should this organisation take into account when deciding whether or not to purchase new hypervisor servers?

Would you advise the organisation to pool their hypervisors together as a distributed system or keep them as separate servers? Why/Why not?

[mod note: edited for eye-hurting font size/bold -JG]
 
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jgreco

Resident Grinch
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May 29, 2011
Messages
12,729
If you want to run iSCSI on FreeNAS, you want 64GB of RAM minimum for that alone.

A Windows 2016 Server is typically allocated 4-8GB of RAM, so you probably want 120-240GB RAM for that. A Debian server would typically be assigned maybe 1GB of RAM, probably more if there was a significant workload, so that's an additional 150GB of RAM.

There's a lot of wiggle room in there depending on what the workloads are, but I wouldn't expect less than 256GB RAM is likely, and more like 512-768GB for typical workloads.

It also feels weedy on the CPU side of things, but again, depends on workload.

Basically you need to figure out what your ACTUAL workloads for each of these servers is, make sure you're within the sizing recommendations provided by Microsoft and Debian, and I can safely tell you that for that many VM's on a FreeNAS system, you probably want 128GB RAM or more for the FreeNAS system, plus probably SSD for backing store, unless you're being gentle on the storage side.
 

Yorick

Neophyte Sage
Joined
Nov 4, 2018
Messages
1,449
I mean, jgreco is spot on with “you need to know your actual workloads”, and: 15 windows servers and 75 Debian on a single Intel Xeon 4110 8 core/16 thread CPU? Doing what, mostly idling along?

If I look at a simple workload like a single ISE node, it wants 8 cores and 16GB just for itself dedicated, in the “small” variety. A lot of workloads have similar or higher requirements.

So without knowing anything, it sounds exceedingly unlikely.

And, yes, you need to look at each application and figure out what its requirements are.

Also: Don’t virtualize the FreeNAS server. Running the storage that the host needs as a virtual machine on the host is, at best, fraught.
 

Dan Tudora

Member
Joined
Jul 6, 2017
Messages
83
I mean, jgreco is spot on with “you need to know your actual workloads”, and: 15 windows servers and 75 Debian on a single Intel Xeon 4110 8 core/16 thread CPU? Doing what, mostly idling along?

If I look at a simple workload like a single ISE node, it wants 8 cores and 16GB just for itself dedicated, in the “small” variety. A lot of workloads have similar or higher requirements.

So without knowing anything, it sounds exceedingly unlikely.

And, yes, you need to look at each application and figure out what its requirements are.

Also: Don’t virtualize the FreeNAS server. Running the storage that the host needs as a virtual machine on the host is, at best, fraught.
guys, guys
do not answer to that question
I am almost sure this is a spy man from google, and if is in lake of ideas want to find a solution to do more with nothing
do not tell the "our secret"
we know secret
when want to do more, buy more hardware
do not tell
please
:D
 

margo

Newbie
Joined
Apr 22, 2020
Messages
3
guys, guys
do not answer to that question
I am almost sure this is a spy man from google, and if is in lake of ideas want to find a solution to do more with nothing
do not tell the "our secret"
we know secret
when want to do more, buy more hardware
do not tell
please
:D
:rolleyes::rolleyes: ,
hhhhhhh it is not a spy. it is a silly question from my lecturer
when it is my first unit studying these things and I didn't understand it and found it hard for me even after two days of researching
that way I am seeking help here :(
 

Yorick

Neophyte Sage
Joined
Nov 4, 2018
Messages
1,449
Aha! So, your lecturer is, if they are any good, looking to see whether you can come back with a plan that will gather data and give a real answer.

In a nutshell:
- These hosts are not likely to have the RAM and CPU to handle 15 Windows and 75 Linux workloads each
- To size new hosts properly, the actual workload requirements are your best bet. If actual ones can't be had, averages need to be used. Adjust for 2-3 years growth. "A DC can't be architected in a vacuum"
- Virtualizing FreeNAS adds complexity in and of itself, and virtualizing on the same host that requires the storage for its VMs is, while doable, again fraught, particularly with failover, as a virtualized FreeNAS requires the HBA to be passed through exclusively for itself. If using FreeNAS, it should be a separate machine, offering storage to the hosts. If HA is required for FreeNAS, go with TrueNAS Enterprise hardware & license instead. Ditto if professional support is required, FreeNAS can have a higher TCO than TrueNAS in a corporate setting.
 

Dan Tudora

Member
Joined
Jul 6, 2017
Messages
83
Please do not use the term RTFM in posts! This is against our community guidelines. Thanks!
:rolleyes::rolleyes: ,
hhhhhhh it is not a spy. it is a silly question from my lecturer
when it is my first unit studying these things and I didn't understand it and found it hard for me even after two days of researching
that way I am seeking help here :(
hello
is the right place to learn
but, I'd suggest reading the documentation more
no offense
succes
 
Last edited by a moderator:

margo

Newbie
Joined
Apr 22, 2020
Messages
3
Aha! So, your lecturer is, if they are any good, looking to see whether you can come back with a plan that will gather data and give a real answer.

In a nutshell:
- These hosts are not likely to have the RAM and CPU to handle 15 Windows and 75 Linux workloads each
- To size new hosts properly, the actual workload requirements are your best bet. If actual ones can't be had, averages need to be used. Adjust for 2-3 years growth. "A DC can't be architected in a vacuum"
- Virtualizing FreeNAS adds complexity in and of itself, and virtualizing on the same host that requires the storage for its VMs is, while doable, again fraught, particularly with failover, as a virtualized FreeNAS requires the HBA to be passed through exclusively for itself. If using FreeNAS, it should be a separate machine, offering storage to the hosts. If HA is required for FreeNAS, go with TrueNAS Enterprise hardware & license instead. Ditto if professional support is required, FreeNAS can have a higher TCO than TrueNAS in a corporate setting.
Thanks for getting back to me so

What specific requirements should this organization take into account when deciding to purchase new hypervisor servers?

Would the organization pool their hypervisors together as a distributed system or keep them as separate servers?
 

Yorick

Neophyte Sage
Joined
Nov 4, 2018
Messages
1,449
You do need to do some of your own work. There are plenty of resources on how to architect virtualized environments, including from VMWare.
 
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