Best Practise - Which SCSI Controller for Windows 2012

[abugeja]

Hi,

We are building a new environment for Windows 2012 servers and was wanting to know what the best practise is for the SCSI controller for Windows 2012 servers. Ive had a look on the net but i cant find a good answer as to which one to select.

LSI Logic Parallel

LSI Logic SAS

VMware Paravirtual

Note that our builds are scripted so we wont be changing this setting based on how many IOPs a virtual machine does for each build. If you could also give myself a reason why that controller should be used that would be great

Virtual Centre Version 5.1.0 Build 1123961

ESXi 5.1.0 1065491

Thanks.

[DavoudTeimouri]

"LSI Logic SAS" has best performance for Windows family OSes (Vista and above).

Also you can use "Paravirtual" on them if you have more than 2000 IOPS.

"LSI Logic SAS" has better performance on lower IOPS compare to "Paravirtual".

I recommend, you should check your server role, if your server is Exchange server, file server or SQL server, you can use "Paravirtual" but if it's DC or DNS server or others, You can use "LSI Logic SAS".

[abugeja]

Thanks for your repsonse. Is any good articles on the net regarding what controller to use? Im yet to find one

[DanielOprea]

Hello,

If there is, look at this article to see the performance of SCSI controllers .

[AlbertWT]

Is there any caveats that we need to know when implementing the Virtual Machine with pvSCSI for large file server ?

based on this article: VMware KB: Configuring disks to use VMware Paravirtual SCSI (PVSCSI) adapters it says that

• Do not use PVSCSI on a virtual machine running Windows with spanned volumes. Data may become inaccessible to the guest operating system.

So when the 2 TB NTFS - GUID partition table is expanded to 16 TB while connected to SCSI 1:0 using pvSCSI, the datamight get corrupted or not supported by VMware or Microsoft ?

[JPM300]

Hey AlbertWT,

You woudln't want to use Paravirtual if you are going to have 8x2TB VMDK disks in windows with a Windows Dynamic Disk SPAN.  If you keep the disks unspanned then its fine, but if you convert them to dynamic disks and span them across each other to create 1 large 16TB disk then don't use a Paravirtual SCSI controller for that.   I would reccoemend avoiding windows SPAN's as they can be problimatic and would keep the disks at 2TB a piece and create your file share accrodingly.  If you require some kind of central share name you can use Windows DFS to accomplish this while keeping the disks seperated.

[AlbertWT]

JPM300,

What I'd like to use is just one single Physical RDM LUn that can be expanded from 2 TB into let say 4 TB later on in the future. I'm not going to span it across two different Physical RDM LUNs, it will be just one.

So in this case is it still recommended ?

The rason I want to use pvSCSI is that this file server will be busy accessed by 650+ users and many other application reading & writing into it. 24x7.

[JPM300]

In that case you will want to formate the RDM as a GPT and it shouldn't be an issue.  I don't belive paravirtual has any issues with GPT and couldn't find anything stating so.  If you keep the drive as MBR or Dynamic its max size is 2TB.

The article is talking specifically about a Windows SPAN which takes two disks and makes them one.  Having a 2TB RAW disk that will eventually expand to 4TB is still one disk and should be fine.

Hope this has helped.

[AlbertWT]

Cool, thanks JPM

yes it will be formatted with GPT instead of MBR, but the filesystem will still be NTFS.

[JPM300]

Yup you should be good to go then.

[anthonyu]

you should use either lsi logic sas or paravirtual.

the IOPS they can provide are more based off of the backend storage they run on
why lsi logic sas and not lsi logic Parallel: LSI logic SAS supports SCSI 3 persistence reservation need to be validated for Microsoft clustering
Paravirtual will benefit it the virtual machine uses 2000 IOPS or more because with Paravirtual it will not send an interrupt for every IO instead when it gets enough requests it sends 1 interrupt and passes all the IO down. this will benefit in less CPU overhead of Disk intensive machines

[sfundakowski]

On a related note,

Can someone tell me the 'cost' in terms of resources, etc, (if any) of using the paravirtual drivers ???

Put another way, 'why not use them instead of LSI drivers ???'

Is there a 'cost' or overhead associated with using them?  What is/are the downside/s?

I understand that there are compatibility issues with different VM versions, versions of VMware, OS's, boot disks, etc, but if you are not concerned with those then why not use the paravirtual SCSI drivers instead ?

Not to get off-topic, but similarly, I would like to know the same information regarding using the VMX3NET drivers versus others (e.g. E1000, etc)?  Why not ??

If these drivers out perform the others, why would I not want to build my VM's with these drivers instead ?

Thanks,

Steve

[anthonyu]

In esxi 5x and below you have reasons to use each storage controller and nics. First off storage

Parravirtual scsi

this adapter is good, as stated before, for high disk io workloads  (2000 iops or more). The reason is, for every io sent to the controller on lsi and bus it requires an interrupt to the cpu, so for high io workloads this will require more cpus to handle the interrupts. Parravirtual adapters will que the ios until it has enough "in the bank" to warrant an interrupts. This means that for high io workloads it will require less cpus and gives better consolidation ratios on your host. However if the vm does not generate the ios required it will cause slow disk performance. Also in 5x Parravirtual adapters can not be used in mscs; however in 6 it can.

Network cards

when ever possible use vmxnet as it provides many features, such as:

-multiqueue (receive-side scaling for Windows)

-ipv6 off-load

-msi/msi-x

When not to use vmxnet3, the biggest reason that i found on why not to use vmxnet3 comes down to os and application issues. For example if you are using citrix pvs or sccm to deploy out vms running windows 2k8(r2) or windows vista/7. microsoft provided a patch that you had to install otherwise your vm would blue screen. Or applications that need a certain network card to be installed, as e1000 is the most common, the application would most likely be able to detect it.