Virtualization Software - HP 3PAR StoreServ 7200 2-node Administrator's Manual

database of a particular group of users, enhances the performance stability for mail databases for
other users and for other applications on the HP 3PAR StoreServ Storage systems.
Microsoft Exchange is a highly interactive software, and its users demand a swift response to
mouse clicks in the Outlook client. To prevent Microsoft Exchange from reporting errors, be careful
to ensure that volumes receive enough IOPs and throughput so that the Microsoft Exchange server
delivers sufficiently low I/O response times.

Virtualization Software

Virtualization platforms, such as VMware vSphere and Microsoft Hyper-V, make use of container
files to store one or more virtual hard disk drives used by virtual machines. Each container file is
built on one or more LUNs accessed over a SAN. Adding the LUNs that make up the container
file to a VVset permits application of a QoS rule. This rule will control the IOPS and/or bandwidth
for all virtual machines (VMs) whose virtual hard drives are carved out of that LUN. Be careful to
ensure that there is enough bandwidth and IOPS in the QoS rule, so that the applications running
on the VMs can deliver acceptable I/O response times.
QoS I/O control operates on all VMs sharing a VMware datastore and, in some cases, this level
of control may not be granular enough. Recent versions of VMware offer three native types of I/O
resource control. Their characteristics, together with those of QoS, are listed in
163).
Table 16 VMware I/O Resource Control
Control Mechanism
I/O control technique:
Reacts on:
Granularity:
Managed from:
Availability:
1, 2, 3
1
Distributes Resource Scheduler
2
Storage I/O Control
3
Adaptive Queue Depth
HP 3PAR Priority Optimization QoS rules operate on volumes inside VVsets on an HP 3PAR StoreServ
system. QoS rules are agnostic for the application type they manage. A QoS rule, on a VVset that
contains one or more VVs that make up a datastore, controls the I/O across all VMs using that
datastore. This could be suboptimal, however, as some VMs need more I/O resources than others.
Combining QoS with SIOC offers I/O control up to the level of an individual VM—an I/O share
and an optional IOPS limit defined per VM distribute the available I/O capacity in a fair way
across VMs, ensuring that no single VM consumes all the I/O provided to the VVset through QoS
settings. Note that SIOC will not respond to queue-full messages from QoS directly.
HP 3PAR Priority Optimization can also cooperate with AQD to manage I/O. AQD handles I/O
congestion in the I/O path to the datastore LUN. It does so by halving the queue length to the LUN
VMware Storage DRS
HP 3PAR QoS
Limit IOPS and Migrate VM to other
bandwidth datastore
None I/O latency and space
utilization
All VMs in datastore Single VM
VV
HP 3PAR MC VMware vSphere
HP 3PAR OS 3.1.2 vSphere 5.0 and later
MU2 with Enterprise Plus
license
Table 16 (page
1 2
VMware SIOC VMware AQD
Control queue depth Control queue depth
of datastore SAN LUN of datastore SAN LUN
in VMkernel; VM in VMkernel
shares enforced
I/O latency Queue Full or Device
Busy at LUN or port
level
All VMs in a single All hosts using the
datastore SAN LUN for the
datastore or a
particular port on the
3PAR
VMware vSphere VMware vSphere
vSphere 4.1 and later vSphere 3.5 U4 and
with Enterprise Plus later with Standard
license license
Using HP 3PAR Priority Optimization 163
3