Contributor
Contributor

Slow performance and speed in VMware ESXi 5

Dear all,

I have a VMware ESXi 5 server with nine VPS in my office. I don't have any problem with this server since this week. All virtual machines which is installed on it become slow in performance and in speed specially SharePoint 2010 virtual machine server. VMware vSphere Client environment is very slow and some time "Not Responding". Shutting down the virtual machines and VMware server and turning them on again will fix the problem, but the next day I have the same problem. I don't know what is the reason. Anyone can explain about this issue and its reason and how to fix it?

Thanks.

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10 Replies
Leadership
Leadership

Please provide some details about the host system (vendor, disks, RAID controller, ...).

In case you are using a RAID controller with battery-buffered write-back cache, double check whether the battery is still ok.

André

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Contributor
Contributor

Main: Intel S1200BTL

CPU: Intel Xeon 1230

One hard disk: 2 TB (No RAID)

Ram: 16 GB

If you need any details further let me know.

Thank you.

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Virtuoso
Virtuoso

You're running nine VMs on that?

It's a reasonably safe bet that you're exceeding the potential of the hardware, particularly where it appears there's a single, uncached, SATA hard disk.

And < 2GB RAM per server, where those servers include something like Sharepoint, is way under spec.

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Contributor
Contributor

Sorry for late, I was sick.

Always one of the nine VMs is off but I can't delete it at this time. SharePoint 2010 server has 4 GB of RAM. In fact, all of VMs have more than 2 GB RAM or equal except three VMs: Accounting Server - 1 GB, WIndows 2003 Server (DC) - 1 GB, Print Server - 512 MB (for printing and faxing).

I think that SharePoint 2010 is a problem but I don't know how to fix it to improve speed and perfomance. When server is slowing in speed, shutting down the VMs will take a long time about 15 minutes !!!

How can I improve performance in VMware vSphere environment. Please say your recommendations to fix this problem.

Thanks.


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Hot Shot
Hot Shot

Hi,

VMs runs on ESXi (datastore with vmfs) are very very slow if server is without controller with cache and battery !

Only on controller with cache and battery is possible (safely) enable write back cache mode

a than performance in ESXi is OK.

Try simple test.

In Browse Datastore do copy any large vmdk to another folder.

During this operation look on Performance Tab (Advanced) and switch to Disk.

What is its maximum speed here? I predict 10MB/s and less...

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Contributor
Contributor

Thanks for replying,

Here is my disk performance chart during copy process between 10:05 AM and 10:15 AM on screenshot.

Any suggestion will be appreciated.
Disk Performance.PNG

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Enthusiast
Enthusiast

Almost certainly your single SATA cannot keep up with the IOPs you vms demand. Not to mention that is pretty big single point of failure for you. Look at the read/write CMD/s stats.

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Hot Shot
Hot Shot

Hi Hojjat,

I thought that it will be worse but you still have poor disk performance on your server.

I can see this:

Highest Latency:     25ms

Read rate:               max. 25MB/s

Write rate:               max. 50MB/s

Usage:                    75MB/s (read + write)


Why is write rate twice larger than read rate?

Because hypervisor zeroes disc space before writing data. This is design, safety reasons.

Of course if controller have cache and battery zero fill is ignored and it will never be written to disk surface.


In addition, ESXi waits for write operation confirmation.

If you have controller with cache and battery and if write back cache mode is enabled (default),

hypervisor gets this confirmation without delay.

Result:

Your disc subsystem have maximum rate 25MB/s only a this is very slow speed !

I can see values up to 90MB/s on my notebook with antivirus.


Solution:

Buy raid controller with cache and battery.


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Contributor
Contributor

Thank you so much,

According to your correct suggestion, RAID controller is the best choice for our problem, but for a special condition we can't purchase it for our ESXi server.

Can we solve this problem without any controller or not? Because we didn't have this problem for a year.

Can VM Migration cause of problem or not? I migrated one VM from another ESXi server to this server.

Thanks for your solution.


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Expert
Expert

That one VM you migrated in may have been the "straw that broke the Camels back". Meaning you were running fine till you added that other VMa nd the additional load is causing your slowness.

You can solve the issue without buying a caching controller by bringing up another ESX server and move some VM's to it to spread the load.

Or, you can get a caching RAID controller.

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