Comments on: vSphere performance http://www.yellow-bricks.com/2009/05/19/vsphere-performance/ Building blocks for virtualization... Thu, 18 Mar 2010 19:25:38 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Duncan Epping http://www.yellow-bricks.com/2009/05/19/vsphere-performance/comment-page-1/#comment-3547 Duncan Epping Wed, 20 May 2009 21:33:50 +0000 http://www.yellow-bricks.com/?p=3180#comment-3547 As Toha already mentioned, PVSCSI doesn't keep you from VMotioning. VMDirectPath I/O does. http://www.vmware.com/files/pdf/VMW_09Q1_WP_vSphereStorage_P10_R2.pdf As Toha already mentioned, PVSCSI doesn’t keep you from VMotioning. VMDirectPath I/O does.

http://www.vmware.com/files/pdf/VMW_09Q1_WP_vSphereStorage_P10_R2.pdf

]]> By: daniel http://www.yellow-bricks.com/2009/05/19/vsphere-performance/comment-page-1/#comment-3543 daniel Wed, 20 May 2009 11:14:21 +0000 http://www.yellow-bricks.com/?p=3180#comment-3543 @jonath - I certainly agree with the single point of failure that is 4-way machines and larger, in order to trust one piece of hardware with more and more VM's we need even more fault tolerance in the hardware/hypervisor, the loss of a CPU or DIMM should affect only the VM's using those resources, not the entire host. Until then you're better off scaling out instead of up. @jonath – I certainly agree with the single point of failure that is 4-way machines and larger, in order to trust one piece of hardware with more and more VM’s we need even more fault tolerance in the hardware/hypervisor, the loss of a CPU or DIMM should affect only the VM’s using those resources, not the entire host. Until then you’re better off scaling out instead of up.

]]> By: toha http://www.yellow-bricks.com/2009/05/19/vsphere-performance/comment-page-1/#comment-3542 toha Wed, 20 May 2009 10:55:32 +0000 http://www.yellow-bricks.com/?p=3180#comment-3542 pvscsi is to disk IO what vmxnet is to networking, it does not stop you doing vmotion. You can boot Windows from pvscsi controller if you copy pvscsi driver to floppy and feed it to Windows during installation. Linux will boot fine also from pvscsi adapter if you know Linux well enough to fiddle with driver modules. pvscsi is to disk IO what vmxnet is to networking, it does not stop you doing vmotion. You can boot Windows from pvscsi controller if you copy pvscsi driver to floppy and feed it to Windows during installation. Linux will boot fine also from pvscsi adapter if you know Linux well enough to fiddle with driver modules.

]]> By: jonatj http://www.yellow-bricks.com/2009/05/19/vsphere-performance/comment-page-1/#comment-3540 jonatj Wed, 20 May 2009 05:56:54 +0000 http://www.yellow-bricks.com/?p=3180#comment-3540 The new performance gains are very impressive. I couldn't believe my eyes when I saw the 320 powered on VM limit for ESX/ESXi. Now that you can have 64 cores and 1TB of RAM on a server the consolidation possibilities are insane. I just wonder the best way to spec a server so that you don't have a single point of failure. I've already had a Purple Screen of Death because of a bad DIMM. DRS is nice and all, but it's still an outage for the 25 VMs on the physical host. With FT's 1vCPU limitation, its not quite the perfect solution yet. So the 320 to 1 consolidation that's possible on one host is frightening. How do you guys spec your hardware? The new performance gains are very impressive. I couldn’t believe my eyes when I saw the 320 powered on VM limit for ESX/ESXi. Now that you can have 64 cores and 1TB of RAM on a server the consolidation possibilities are insane. I just wonder the best way to spec a server so that you don’t have a single point of failure. I’ve already had a Purple Screen of Death because of a bad DIMM. DRS is nice and all, but it’s still an outage for the 25 VMs on the physical host. With FT’s 1vCPU limitation, its not quite the perfect solution yet. So the 320 to 1 consolidation that’s possible on one host is frightening.

How do you guys spec your hardware?

]]> By: Jason Boche http://www.yellow-bricks.com/2009/05/19/vsphere-performance/comment-page-1/#comment-3539 Jason Boche Wed, 20 May 2009 01:14:27 +0000 http://www.yellow-bricks.com/?p=3180#comment-3539 pironet is correct in that you cannot boot from the paravirtualized SCSI controller which means you'll have a minimum of two SCSI controllers per VM running the paravirtualized controller. I'm not sure if I'd consider this a "serious" caveat, but it is something to be aware of anyway. Not being able to VMotion is a serious enough caveat though. pironet is correct in that you cannot boot from the paravirtualized SCSI controller which means you’ll have a minimum of two SCSI controllers per VM running the paravirtualized controller. I’m not sure if I’d consider this a “serious” caveat, but it is something to be aware of anyway.

Not being able to VMotion is a serious enough caveat though.

]]> By: NiTRo http://www.yellow-bricks.com/2009/05/19/vsphere-performance/comment-page-1/#comment-3538 NiTRo Tue, 19 May 2009 22:54:37 +0000 http://www.yellow-bricks.com/?p=3180#comment-3538 I heard the pvscsi adapter makes vmotion impossible. That would make a lots of "but" for me... I heard the pvscsi adapter makes vmotion impossible. That would make a lots of “but” for me…

]]> By: JustinE http://www.yellow-bricks.com/2009/05/19/vsphere-performance/comment-page-1/#comment-3537 JustinE Tue, 19 May 2009 18:36:22 +0000 http://www.yellow-bricks.com/?p=3180#comment-3537 Etienne, It appears as a totally different hardware device in your VMs. There are 4 choices for storage controllers in vSphere: BusLogic, LSILogic (Fusion MPT), LSILogic SAS (useful for Server 2008 clustering), and PVSCSI. Unfortunately booting from the PVSCSI adapter is not supported at this time (not saying it won't work...) so you're supposed to have a boot volume and then a data volume on the PVSCSI controller. Etienne,
It appears as a totally different hardware device in your VMs. There are 4 choices for storage controllers in vSphere: BusLogic, LSILogic (Fusion MPT), LSILogic SAS (useful for Server 2008 clustering), and PVSCSI.
Unfortunately booting from the PVSCSI adapter is not supported at this time (not saying it won’t work…) so you’re supposed to have a boot volume and then a data volume on the PVSCSI controller.

]]> By: pironet http://www.yellow-bricks.com/2009/05/19/vsphere-performance/comment-page-1/#comment-3534 pironet Tue, 19 May 2009 16:00:12 +0000 http://www.yellow-bricks.com/?p=3180#comment-3534 LSI and Buslogic are emulated SCSI-2 drivers. pvscsi drivers gives direct access to the HBA hence the 'pv' for paravirtualization. The performance gain comes certainly from the 'pv' thing... Althought there is a serious caveat of this technology is that the guest OS still has to boot from a non PVSCSI adapter, LSI by default. Now I'm not sure it does increase consolidation ratio because in a shared hardware environment, giving priority or direct access to a particular guest just reduce the 'shares' for the other guests and in fine reduce the consolidation ratio. Cheers, Didier LSI and Buslogic are emulated SCSI-2 drivers. pvscsi drivers gives direct access to the HBA hence the ‘pv’ for paravirtualization.
The performance gain comes certainly from the ‘pv’ thing…

Althought there is a serious caveat of this technology is that the guest OS still has to boot from a non PVSCSI adapter, LSI by default.

Now I’m not sure it does increase consolidation ratio because in a shared hardware environment, giving priority or direct access to a particular guest just reduce the ’shares’ for the other guests and in fine reduce the consolidation ratio.

Cheers,
Didier

]]> By: Etienne Pouliot http://www.yellow-bricks.com/2009/05/19/vsphere-performance/comment-page-1/#comment-3533 Etienne Pouliot Tue, 19 May 2009 15:38:53 +0000 http://www.yellow-bricks.com/?p=3180#comment-3533 Is using that new paravirtualized SCSI adapter just a matter of installing new VMware tools that come with Vsphere ? Is using that new paravirtualized SCSI adapter just a matter of installing new VMware tools that come with Vsphere ?

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