Troubleshooting VMWare ESX 4.0

I am currently running an esx 4.0 (261974) server with 8 (xp) virtual machines on it. I manage the machines using VMWare vSphere 4 Essentials running on a windows server

We seem to be getting a large number of delays on the virtual machines, it works great in bursts but then at times it can stop for a long time before catching up again.

I am not familliar with VMWare and have accepted the basic installations of ESX 4.0 and vSphere to get this up and running.

the ESX server has 4 CPUs x 3GZ (intel xeons) and 16g of ram. the vms have been allocated 1gb each on vSphere.

I'm looking initially to update the nic cards on the vms (windows drivers) which are showing as VMWare accelerated AMD PCNet Adapters (driver ver2.0.3.6 date 1/20/09).

Can I get some other suggestions on what to check?


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bgoeringConnect With a Mentor Commented:
The battery backup will dramatically help write performance because it will allow you to configure "write back" caching as opposed to only allowing "write through" caching. With write back, the host OS (ESX) will be able to continue as soon as the data is in the controller cache, and not have to wait until the data is actually on disk.

SAS drives - much faster than SATA and highly recommended fro I/O intensive workloads like fileshares and database.

I would recommend with your 4 drives configure 3 in a RAID 5 set, and keep the 4th as a hot spare.

For my purposes RAID 5 has always been sufficient for most VM activity - you do suffer a small write performance as opposed to RAID 10, but you pay a significant penalty in amount of space available for your use. Only thing I use RAID 10 for is OLTP database log files.

Good Luck
Look at the performance tab in the vSphere client and see if you can spot any contention hot-spots, I would focus on Memory and Disk,

Good Luck
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Please can you expand on stop?

How are you accessing the virtual machines via RDP?

Do the VMs actually stop and not respond, e.g. no response to pings, hence your NIC investigation?

What workload are the Windows XP virtual machines doing, is it just one VM or all eight that "stop"?
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
or are you using the VI Client to access the consoles of the VMs? If you are using the VI Client to access the XP VMs, try using RDP, I've seen Windows Clients (XP, Vista, WIndows 2003 Server) with low memory when using the VI Client, stop responding for several minutes, because the VI Client seems to be hungry for resources, and the somestimes the Windows Virtual Memory box appears, this is with computers/workstations and servers with 512MB or less.
Brett DanneyIT ArchitectCommented:
Do not update the NIC card drivers. Make sure you have VMware tools installed on each VM rather.
ITOSAuthor Commented:
What I mean by Stop is that the machine will freeze up completely and then resume after a period of time (can be 10 seconds, can be up to 4 minutes). I'm using PanoManager to connect to each VM but getting the same performance issues when using RDP.

The workload isn't huge, usual Office apps and a couple of custom ones but nothing major. They are XP machines.

I was going to update the NIC drivers on the vms to VMXnet3 (as is the option found within vCentre to change it) - is this still a bad idea?

I think the problem is relating to disk I/O. Looking through logs I can see the performance spiking. Nothing else (cpu, memory) is showing large usage.

I think the question may be how the hypervisor was set up. There are 5 disks in a raid 5 array (5 x 500GB) - when asked to install ESX it was installed on the raid partition. There was no split up between the OS and the storage on the box. Can someone give pointers on how this could be better set up so that performance on the disks would be improved while getting maximum storage out of the 3TB of disks available. Is Raid 5 the right one to use? can you split up the OS from the storage space?

Thanks for your help!
Raid 5 is good for most applications - I use raid 5 for about everything except database luns. If these are SATA drives you might be pushing the limit if you have active VMs all hitting the same array, if they are SAS I wouldn't expect to be seeing any problem. No matter how slow the disk storage a 4 minute freeze up I don't think I can attribute directly to the disk configuration.

There should be no issues updating the NIC cards to vmxnet3 - that offers the best performance and the least overhead for the vm. Just make sure vmware tools are up to date on each guest xp before you update the NIC.

Tell me a bit more about the ESX server hardware. HP? Dell? Model? Raid controller type?
ITOSAuthor Commented:
Your point on SAS drives is interesting. We are using 2.5" sata 7200rpm drives on a HP DL 360 G5.
The controller is a HP Smart Array P400 controller. We have ordered a battery backup and are expecting it in the next couple of days.

I've just ordered 4 10000rpm SAS disks to replace the sata's - i'm probably going to rebuild the server this weekend. Any advice on building the new esx server? (raid configuration/installation of os & datastore). I'm a novice on VMWare so would appreciate some tips on building the new server.
ITOSAuthor Commented:
Thanks bgoering....really appreciate it. Will get the hardware at the weekend and let you know how it goes.
ITOSAuthor Commented:
512mb memory and battery backup module seems to have sorted out the issue along with SAS disks.
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