duhaas
Enthusiast
Enthusiast

CPU USAGE I/O Wait MS

Looking for some advice on areas to look @.  I have the following:

Metric_Graph_280_665.png

If I look into the spike, I don't see much write or read latency back to disk from this vm:

Metric_Graph_280_760 (2).png

latency is relatively low

Metric_Graph_280_665 (1).png

but if I look @ I/O wait for that same period seems high, just trying to understand what else I might want to look into?  seems that IO wait could become an issue.  Should mention this is a 2008R2 windows box, running SQL server.  LSI logic for storage controller

Tags (1)
0 Kudos
2 Replies
NuggetGTR
VMware Employee
VMware Employee

Hey,

IO wait is basically cpu.wait - cpu.idle - cpu.swapwait which means something in the VM world is causing it. if its not storage, or networking, then you need to look at other things that could be attached to the VM, pci devices, usb devises and believe it or not one of the big offender sis if you leave an ISO attached to the virtual cd drive can cause high wait times.

If everything looks fine and the wait times are impacting performance then you can cause it to crash to get dump data but i recommend talking to VMware support if this becomes an option.

Cheers

________________________________________ Blog: http://virtualiseme.net.au VCDX #201 Author of Mastering vRealize Operations Manager
0 Kudos
mark_j
Virtuoso
Virtuoso

I'm a fan on CPU READY % as it's universal metric typically. Can get in to WAIT, etc after you do an initial problem determination using READY %.

If you find this or any other answer useful please mark the answer as correct or helpful.
0 Kudos