R515/H700 high iowait

G.Bakalarski at icm.edu.pl G.Bakalarski at icm.edu.pl
Wed Jul 18 07:26:20 CDT 2012

> This is with XFS and barriers were left enabled.  We also tested having
> fio write directly to the device.

Hi Mark,

Did you enable any virtualization settings ???
Does your Ubuntu runs on bare metal hardware without
any xen, citrix or whatever???

Did you changes anything in BIOS setting eg.
IOMMU on (DMA virtualisation) ? What is your
C states setting? Is BIOS optimized for Performance
(CPU seting)?

Have you monitored IO behaviour with e.g. iostat -xzk 2 ???
What was a size of queue length? Did it change during tests?
Have you tested IO with another tools like e.g. iozone or others ??



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