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InforMed_Direct
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Sluggish performance of Windows 2003 server

I've decided to start a new thread on this as it's not the same as the original problem. Year old PowerEdge 1850 Dell server with 3GB of memory running fresh install of ESX Server 3.5 Update 1. One single VM installed from scratch running Windows 2003 standard server R2 in x86 mode. The symptoms are that the system runs fine without any crashes or errors in the log but it's very sluggish, but not all the time. When generally moving around the system using a remote desktop, the screen freezes for a few seconds. Performance monitor and task manager don't show any exceptional load on the system - just what I'd expect to see.

The original thread was about slow boot time and I think this is all related. Somebody posted a link to a KB article saying that some systems with particular dual CPUs have slow reboot due to some magic ESX Server does with memory. I suspect that the same issue is actually still happening through the system.

As a guess, I've just reduced the virtual CPUs down from 4 to 1. The PowerEdge has dual CPUs but has hyperthreading, not the more recent dual core.

With only one CPU, so far, the system is much more responsive. But of course, we want to be able run multiple CPUs - this ESX Server is only ever going to run this one VM.

I suspect it's something to do with multi-CPU and memory but I'm not enough of a ESX guru to know what to go looking for. There are many posts on here on similar subjects, many suggesting turning off memory optimisation. Does that sound sensible?

Thanks, Rob.

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khughes
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Did you build the VM out with 4 vCPUs? You might still be using the Multi Processor HAL still. Under the device manager --> Computer you can check to see what HAL you're using. If you run 1 vCPU you should have the single processor HAL. Also I'm sure you're using this since its a built from scratch VM but you're using LSI scsi adapter for your VM hard drive?

  • Kyle

-- Kyle "RParker wrote: I guess I was wrong, everything CAN be virtualized "
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InforMed_Direct
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Yes, the VM was built from scratch on this ESX Server and I'm pretty sure I selected 4 CPUs from the start. I've just shut it down to try out setting Mem.ShareScanGHz to 0 as mentioned in KB article 1004901. I'll bring it back up first to check out the HAL and SCSI adapter.

Cheers, Rob.

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khughes
Virtuoso
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Just a FYI, you don't need to power on the VM to check the SCSI adapater, you can just look at the settings of the VM under the SCSI adapter it'll say BusLogic or LSI

  • Kyle

-- Kyle "RParker wrote: I guess I was wrong, everything CAN be virtualized "
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InforMed_Direct
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Under Computer, it has ACPI multiprocess PC. And yes, it's using the LSI logic SCSI driver.

The KB article I mentioned I thought was just slow reboot but actually it's also "Slow performance of virtual machines that use more than one vCPU on an ESX Server when using certain hardware". So I'll give that a go. This server is just running on VM for now and it's got plenty of RAM - 3GB in host but only 2GB used by VM.

Cheers, Rob.

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InforMed_Direct
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I've changed Mem.ShareScanGHz from 4 to 0, rebooted the ESX and set the CPUs back to four. If anything, this made things worse. It sat at the "Preparing network connections" for a goodly while, took ages sat at the "Loading personal settings (minutes)", lost the RDP connection for about 30 seconds and is maybe more sluggish. Maybe I'm waiching it more closely. I've got performance manager open and it does two weird things - the logging occasionally stops for a couple of seconds with a gap in the log or the logging red line pauses and then quickly catches up with itself before slowing down.

I wonder if it's I/O related maybe? It does seem to be when you load new programs which cause a bit of disk activity.

I've raised a support call on this as this is a rather worrying issue we need resolved.

I'm going to put Mem.ShareScanGHz back to 4 and reduce CPU to one for now...

Cheers, Rob.

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InforMed_Direct
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The basic problem here is that this particular hardware had two CPUs but used hyperthreading not dual core. Whilst creating a VM with four vCPU does work, there is contention between the ESX server and VM use of the CPUs. Hyperthreading really shouldn't be seen as separate processors when building a system. I suggest you forget it's got hyperthreading and say you've just got two CPUs.

Dropping down to two vCPU worked a treat and performance is now fine.

Dual-core (or quad-core) systems don't suffer as bad so you can create a 4 vCPU VM on a dual CPU, dual core system.

Rob.

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InforMed_Direct
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PS. Technical support were excellent on this subject. A credit to the team. This counters my disappointment elsewhere that you can't attach external USB hard drives to an ESX system for backup.

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