Database Reference
In-Depth Information
leveraging physical SAN capabilities such as snapshots that you wish to present to a
physical server for a purpose such as LAN-free backups, if you are not using a backup
solution integrated with the VMware APIs for Data Protection. However, there are no
noticeable performance differences between RDMs and virtual disks on a VMFS file
system, as
Figure 6.14
illustrates.
Figure 6.14
VMFS and RDM performance comparisons: IOPS vs. IO size.
Figure 6.14
illustrates the performance comparison between VMFS and RDM using a
random 50/50 mixed read-write workload pattern and the different IO sizes based on
data published at
http://www.vmware.com/files/pdf/performance_char_vmfs_rdm.pdf
.
Note
Although Virtual Mode RDMs (vRDMs) are included in
Figure 6.14
for
performance comparison, they are not supported for use with Windows
2008 and above failover clustering or SQL Failover Cluster Instances.
Tip
There is a common myth that you can't perform vMotion operations when using
RDMs. This is not the case. VMs configured with RDMs support vMotion, but
