Comments on: Boot from Paravirtualized SCSI Adapter

By: Silver

Silver — Sun, 27 Jun 2010 23:35:55 +0000

I would like to share couple of things I ran into when I tried to convert boot disk to PVSCSI.
Same case has been reported to Vmware support.

The article is here.
http://geeksilver.wordpress.com/2010/06/21/upgrade-esx-3-5-to-vsphere-fixing-part-1-5/

By: Virtu-Al

Virtu-Al — Fri, 19 Mar 2010 13:04:29 +0000

Thanks for the comment, that is really interesting, I am deploying soem Citrix boxes at the moment and whilst I havent done a direct side by side comparison it certainly seams faster to use from the user perspective, perhaps I will have to delve deeper.

By: Rodney de Pater

Rodney de Pater — Fri, 19 Mar 2010 12:57:08 +0000

There has been some follow up performance reports (http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1017652) that show that the pvSCSI adapter may not be the best choice for low IO VMs due to IO coalescing. And the thresholds are substantial.

“..The test results show that PVSCSI is better than LSI Logic, except under one condition–the virtual machine is performing less than 2,000 IOPS and issuing greater than 4 outstanding I/Os…”

Perhaps some perspective – you can expect that for every heavy email user, Exchange will typically generate 1/2 IOPS, so you will need 4000 heavy email users loaded up on an Exchange VM to really take advantage of the pvSCSI adapter.

Now those VMs that trickle feed IO, and with the adapter having to wait for IO to coalesce before dropping it on the (virtual) wire, pvSCSI may introduce additional IO latency.

pvSCSI is brilliant however, as with any tool, needs to be employed appropriately…

Average VMs will be fine with the LSI Logic

By: VMware: Paravirtualisierter SCSI Adapter | linuxvoodoo.de

VMware: Paravirtualisierter SCSI Adapter | linuxvoodoo.de — Thu, 04 Mar 2010 17:51:41 +0000

[...] schönes HowTo mit Screenshots habe ich auf http://www.virtu-al.net gefunden. … other posts by [...]

By: NiTRo

NiTRo — Thu, 21 Jan 2010 00:32:10 +0000

Here is another way to do it without dummy disk (driver injection) http://www.hypervisor.fr/?p=1764

By: Migration PVSCSI automatisée - Hypervisor.fr

Migration PVSCSI automatisée - Hypervisor.fr — Thu, 21 Jan 2010 00:21:47 +0000

[...] effet, comme le décrit Alan sur son blog, la solution la plus facile consiste à rebooter avec un disque temporaire sur un nouveau [...]

By: P2V conversion tips and tricks « UP2V

P2V conversion tips and tricks « UP2V — Sat, 16 Jan 2010 13:18:12 +0000

[...] You might want to take advantage of the latest drivers for virtual SCSI adapters and virtual nic’s available in vSphere 4. To replace the buslogic parallel scsi adapter by the paravirtualized scsi adapter (PVSCSI). This adapter supports if Update 1 is used, also booting from the Paravirtual SCSI adapter. To replace the default SCSI adapter after the conversion has ended, follow the instructions published on http://www.virtu-al.net/2009/12/02/boot-from-paravirtualized-scsi-adapter/ [...]

By: Virtu-Al

Virtu-Al — Mon, 14 Dec 2009 11:44:30 +0000

@Carl Skow Thanks, thats useful to know.

By: Carl Skow

Carl Skow — Thu, 10 Dec 2009 22:50:40 +0000

I just verified with VMware support that pvscsi adapters (as well as vmxnet adapters) are still not compatible with Fault Tolerance. Just a caveat to be aware of.

By: Carl Skow

Carl Skow — Wed, 09 Dec 2009 18:04:12 +0000

Has anyone verified that you can still enable FT with a pvscsi adapter?