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LSI Logic SAS Controller vs Paravirtual Iscsi

sara2000
sara2000 asked
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I have seen a few discussions about LSI Logic SAS Controller and paravirtual iscsi controller.
We have several VMs with LSI Logic SAS Controller and they are running without an issue, I am not sure whether it is necessary to change or not. I was asked to add a few disks to our Exchange server which is running with LSI Logic SAS Controller, I am thinking of adding a paravirtual iscsi controller (iscsi 2, 0)for new disks.
Experts out there, is it recommended to keep both LSI Logic SAS Controller(iscsi 1,0) and paravirtual iscsi controller (iscsi,2,0) on one server?
or Should I stay with the LSI controller or change all to paravirtual do not run with both?
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Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
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Commented:
If you are seeking every single IOP then you could use the Para. Driver but it may not be immediately obvious of the performance increase.

Would we change a current production VM - NO

Unless you are struggling with performance issues which CAN be associated with Disk I/O

New Service New VM then you could look at this for your implementations

Look at Architecting SQL this storage controller is recommended but with all the other needed changed
David Johnson, CDSimple Geek from the '70s
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Commented:
Just for completeness sake it is Paravirtual SCSI not Paravirtual  iSCSI

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Commented:
Thank you for thr info and correction. If we add new disks can we use both scsi controllers? LSI for the current disks and para virtual for new disks,
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Commented:
I would recommend you stick with the LSI.

But yes you can mix if you so wish.

If a new build, you may want to consider Para.

Please see this Whitepaper

https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/solutions/sql-server-on-vmware-best-practices-guide.pdf


and please pay attention to:-

3.8.3.4 USING STORAGE CONTROLLER

4.1.3 Configure PVSCSI Controller

and you may also want to review your networking as well.

e.g. it's NOT just a case of add the Paravirtual Interface, it depends upon the workload of the application/service, and also how you configure and tweak the driver/configuration.

If you just add it, and do nothing, you really are wasting your time ->>> you will see very little benefit.

(and all this depends upon your tiered datastore).

I would recommend you investigate and look at the current performance of the disk subsystem of the VM before making changes.