Hi,
Well, I've found out that disk performance is related to VMware iSCSI storage and the way how RHEL/CentOS handles storage I/O. When using VMware local storage instead of iSCSI, performance is nearly equal in Windows and RHEL/CentOS, but when using iSCSI, RHEL/CentOS has worse performance. I don't have the answer to this.
However, when testing various kernel parameters for RHEL/CentOS I've found out this:
- RHEL 5 kernel parameters for optimal disk performance:
notsc divider=10 elevator=noop
- RHEL 6 kernel parameters for optimal disk performance:
notsc lpj=n elevator=noop
By setting those parameters virtual disk performance on iSCSI storage in RHEL/CentOS is nearly as high as it is in Windows.
Still I don't fully undestand the way VMware handles storage I/O so any further information regarding this topic is welcome.