Multiple Windows guests in Linked Clone

[antechno]

Hi guys,
I have some technical questions.

On my Proxmox 3.4 I have a Windows 7 Template and 30 Linked Clones around connected to it.

Multiples physical users from low profile hardware computer (thin-clients) connect to single clone across RDP protocol, but sometimes some guests hang up or have low performance when big programs (like Matlab/Simulink software) are used

Each single virtual machine clone has actually normal performance and a .qcow2 file image format.

Is a problem for performance to have multiple Windows guests (30 around or more) in Linked Clone connect to Template? Is there a max number of Virtual Machine that Linked Clone mode permit?

I decided this solution to conserve disk space, to allow multiple virtual machines to use the same software installation, and to quickly destroy the Template and relative Virtual Machine linked and recreate them (to update software).

I think that the Full Clone is a probably best solution, but it will take several minutes in the same configuration and more disk space.

Current Technical configuration
DELL PowerEdge R815 WITH:

• 4x AMD Opteron 6380 (2,5GHz, 16C, cache L2 16MB/L3 16MB, Turbo CORE, TDP 115W), DDR3 a 1.600MHz (TOTAL CORE: 64).
  
• RAM MEMORY 512GB (32x16GB RDIMM LV dual rank) 1.600MH.
• 2x HD SATA 500GB (7.2k) in RAID 1 (PROXMOX INSTALLATION).
  
• 4x HD SATA 1TB (7.2k) in RAID 10 (VIRTUAL MACHINE STORAGE).
• PERC H700 controller RAID integrated, 1GB Non-Volatile BATTERY-BACKED cache.
  
• VirtIO driver installed on VM.

Another question:
Upgrading the 4 HD SATA 1TB (7.2k) with 4 SAS DISK 10K i think is usefull to achieve better performance, is it right?

Thanks a lot for your suggestions.

 

[Richard]

On my Proxmox 3.4 I have a Windows 7 Template and 30 Linked Clones around connected to it.

Multiples physical users from low profile hardware computer (thin-clients) connect to single clone across RDP protocol, but sometimes some guests hang up or have low performance when big programs (like Matlab/Simulink software) are used

Each single virtual machine clone has actually normal performance and a .qcow2 file image format.

Is a problem for performance to have multiple Windows guests (30 around or more) in Linked Clone connect to Template?

No

Is there a max number of Virtual Machine that Linked Clone mode permit?

No

Upgrading the 4 HD SATA 1TB (7.2k) with 4 SAS DISK 10K i think is usefull to achieve better performance, is it right?

Yes

 

[sherminator]

Current Technical configuration
DELL PowerEdge R815 WITH:

• 4x AMD Opteron 6380 (2,5GHz, 16C, cache L2 16MB/L3 16MB, Turbo CORE, TDP 115W), DDR3 a 1.600MHz (TOTAL CORE: 64).
  
• RAM MEMORY 512GB (32x16GB RDIMM LV dual rank) 1.600MH.
• 2x HD SATA 500GB (7.2k) in RAID 1 (PROXMOX INSTALLATION).
  
• 4x HD SATA 1TB (7.2k) in RAID 10 (VIRTUAL MACHINE STORAGE).
• PERC H700 controller RAID integrated, 1GB Non-Volatile BATTERY-BACKED cache.
  
• VirtIO driver installed on VM.

I also guess that storage I/O is your bottleneck.
I'm not familiar with this cloning stuff - but wouldn't it be smart to put the base template on an SSD?

Greets
Stephan

 

[antechno]

Thankes for the answers.
For better I/O results would be appropriate to replace also the current hypervisor disk (SATA) with faster SAS (10K or 15K) o would not have any kind of improvement?

From DELL support I have known that on my RAID controller could be used one SSD disk in "cachecade" mode that could improve the performance of the Virtual Array. Any related experiences with Proxmox?
https://www.dell.com/downloads/global/products/pedge/en/perc-h700-cachecade.pdf

 

[sherminator]

For better I/O results would be appropriate to replace also the current hypervisor disk (SATA) with faster SAS (10K or 15K) o would not have any kind of improvement?

The disks where the Proxmox installation lives is not that much relevant concerning the I/O of your VMs.

From DELL support I have known that on my RAID controller could be used one SSD disk in "cachecade" mode that could improve the performance of the Virtual Array. Any related experiences with Proxmox?
https://www.dell.com/downloads/global/products/pedge/en/perc-h700-cachecade.pdf

Hm... according to this whitepaper a caching SSD can improve the I/O by up to 50%. To me that sounds like improving from very slow to slow. How much data is the base template? I would really consider migrating it to an SSD if possible.

Greets
Stephan

 

[antechno]

the base template has a virtio disk of 80 GB size with 65 GB of space used at the moment (du -sh command)
-r--r--r-- 1 root root 80G Feb 13 18:07 base-111-disk-1.raw

Each clone VM has around 2 GB file:
-rw-r--r-- 1 root root 2.0G Feb 16 12:29 vm-160-disk-1.qcow2

cache=writeback is enable on virtio disks (template and clones)

 

[bonibom]

I am thinking about the same configuration in order to save SSD disk space. But I am not sure if this is compatible with Windows OS EULA. I use many different VM starting from windows 7. Will it be legitimate to use one retail (or MAC) key accross many number of linked clones? If someone aware of Windows OS licesning details in this I will very appreciate the answer.