Drive performance in VMware environments with IBM FlashSystem. IBM flash storage delivers extreme, scalable performance for virtualized infrastructure.

1. IBM Systems and Technology
Technical White Paper
May 2014
Drive performance in
VMware environments
with IBM FlashSystem
IBM flash storage delivers extreme, scalable
performance for virtualized infrastructure
Abstract
Explore the advantages of using
IBM® FlashSystem™ storage to run
mission-critical workloads in VMware
vSphere environments to help improve
performance, reduce storage costs and
scale on demand to support changing
business needs.
Introduction
Organizations are increasingly turning to virtualized environments
to run their top-tier workloads so they can get the same benefits of
virtualization—such as management efficiency, rapid provisioning and
increased uptime—already provided for their lower tier workloads.
Yet maintaining high performance and reliability for top-tier workloads
typically requires more hardware resources than needed for lower tiers.
And this can add stress to already tight technology budgets.
By using IBM FlashSystem 840 in a virtualized VMware vSphere
environment, organizations can achieve orders-of-magnitude-faster
performance than with hard disk drive (HDD) storage systems. This
performance is particularly vital for mission-critical applications, which
depend upon online transaction-processing (OLTP) workloads with
microsecond response times.
This white paper presents the performance test results of deploying
FlashSystem 840 with OTLP workloads running on VMware vSphere
infrastructures. Our test used the DVD Store benchmark, which is the
OLTP portion of the standard VMware VMmark suite, to apply OLTP
loads to the FlashSystem 840 storage array. The test results were then
compared to a baseline HDD storage system, showing substantial
performance improvement when using FlashSystem 840.

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Technical White Paper
May 2014IBM Systems and Technology
With the combination of FlashSystem storage and VMware
vSphere infrastructures, organizations can increase virtual
machine (VM) density and mixed-workload implementations
with confidence. This paper shows how FlashSystem 840 pro-
vides extremely fast, low-latency shared storage between
vSphere ESXi hosts and thus enables the management efficien-
cies provided by VMware vSphere such as vMotion and High
Availability (HA). Organizations can then reduce their storage
costs, optimize CPU utilization and scale on demand to meet
rapidly changing business needs.
Note: This paper requires basic knowledge of FlashSystem
storage arrays, VMware vSphere ESXi installation and
configuration, and the VMware vSphere web client.
Key components used for VMware testing
This section describes the main components used in our perfor-
mance tests: FlashSystem 840, VMware vSphere ESXi, the
VMware VMmark benchmark and the DVD Store test suite.
FlashSystem 840
IBM FlashSystem 840 delivers high performance, efficiency and
reliability for shared enterprise storage environments, where
organizations require near-continuous availability of critical
applications. FlashSystem 840 can either complement or replace
traditional HDD arrays in many business-critical applications,
such as:
●● Online transaction processing
●● Business intelligence
●● Online analytical processing
●● Virtual desktop infrastructures
●● High-performance computing
●● Content-delivery solutions (such as cloud storage and
video on demand)
IBM FlashSystem 840
FlashSystem 840 is comprised of a 2U enclosure containing
redundant and hot-swappable flash modules, power supplies,
batteries, interfaces and RAID controllers. Multiple interfaces
are supported, including 16 Gb or 8 Gb Fibre Channel,
40 Gb QDR InfiniBand and 10 Gb Fibre Channel over
Ethernet (FCoE).
FlashSystem 840 is designed to be fast and efficient. Its low
energy consumption and fast, reliable operation can help
increase revenue [return on investment (ROI)] and save
money [total cost of ownership (TCO)]. In addition, organiza-
tions can use FlashSystem arrays to help improve performance
and efficiency without having to re-architect their applications
or underlying storage infrastructure. Some potential benefits
of using FlashSystem storage include:
●● Fast applications
●● Fewer software licenses required
●● Fewer servers required
●● Energy-efficient data centers
●● Stable applications
●● Predictable performance
●● Balanced architectures
●● Improved CPU availability

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Technical White Paper
May 2014IBM Systems and Technology
In addition, FlashSystem 840 helps organizations achieve a
competitive advantage in a world of 24x7 continuous and com-
plex operations. It delivers low latency and high input/output
operations per second (IOPS) at an economical price. And,
when combined with IBM SAN Volume Controller (SVC),
FlashSystem 840 provides advanced storage functionality
such as IBM Real-time Compression™, Remote Mirroring,
IBM FlashCopy® and VMware vSphere APIs for Array
Integration (VAAI).
VMware vSphere ESXi
VMware ESXi provides the foundation for building a reliable
and dynamic IT infrastructure. This proven hypervisor is
designed to abstract processor, memory, storage and networking
resources into multiple virtual machines that can run separate
operating systems and applications. VMware ESXi is one of
the most widely deployed hypervisors, delivering high levels
of reliability and performance to organizations of all sizes.
VMware ESXi has an ultra-thin architecture that does not
require a general-purpose operating system. This can help
improve security and reliability because the attack surface is
small and there is less code to patch. Thanks to its small
footprint and hardware-like reliability, VMware ESXi is
often built directly into industry-standard x86 servers from
leading server manufacturers such as IBM, Dell, HP and
Fujitsu-Siemens. VMware ESXi was designed with simplicity
in mind. Its menu-driven startup and automatic configurations
make it easy to get started with VMware virtualization.
By deploying VMware for virtualized IT infrastructures,
organizations can:
●● Decrease hardware, energy and cooling costs by running
multiple operating systems on the same physical server
●● Lower management costs by reducing the hardware footprint
in the data center
●● Help ensure high levels of availability for the most business-
critical applications
●● Consolidate hardware resources with one of the most widely
deployed, production-proven, and secure server virtualization
platforms
Key features of VMware ESXi include:
●● A 64-bit architecture for improved performance and support
for up to 4 TB RAM on physical hosts
●● Performance optimization for virtualized workloads
●● Application awareness to help improve application uptime
●● Hosting of workloads of virtually any size
●● Support for 64 virtual CPUs per virtual machine
(Virtual SMP)
●● VMDirectPath for virtual machines to help enhance
processor efficiency
●● Improved power management
VMware VMmark
VMware VMmark is a benchmarking tool that enables vendors
and other organizations to evaluate the performance of their
virtualization environments. Virtualized environments typically
run mixed workloads. It is common to have mail servers, OTLP
databases and application servers running on the same VMware
ESXi host. For this reason, performance tests targeted at spe-
cific applications are not effective for testing an entire shared
environment. In contrast, VMmark is designed to test mixed
workloads.
To address mixed workloads, VMmark implements a unit of
work called a tile. A tile consists of a collection of virtual
machines. The quantity of tiles is increased until the infrastruc-
ture is no longer capable of adequately handling the workload.

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Technical White Paper
May 2014IBM Systems and Technology
A VMmark tile contains three separate application workloads.
Each workload contains multiple virtual machines. The
applications are as follows:
●● Mail server: Microsoft Exchange 2007
●● Web 2.0 application: Olio
●● E-commerce application: DVD Store
The VMmark suite as a whole is not a storage-dependent
workload. To drive a storage-intensive workload to the
FlashSystem 840 array, IBM selected the DVD Store portion
of the VMmark benchmark. The DVD Store test suite
represents an OLTP application that aligns with the use case
of FlashSystem storage.
For more information on VMmark, refer to:
www.vmware.com/products/vmmark/overview.html
DVD Store database test suite
The DVD Store database test suite is an open-source
e-commerce application that was originally developed by Dell
and later enhanced by VMware and others. The application
represents an online DVD store that allows users to browse and
purchase DVDs. The test suite provides a load driver for both
the web and database tiers. This allows for easy testing of the
full application stack or only the database component. For more
information on the DVD Store database test suite, refer to:
linux.dell.com/dvdstore/
Test configuration
This section describes our performance testing configuration.
IBM performed the VMware testing on an IBM System x®
server with eight virtual machines, one running the driver appli-
cation and the other seven running Microsoft SQL 2008 R2.
The virtual machines were located on a single VMware ESXi
host with dedicated resources assigned to each virtual machine.
The driver VM’s vmdk files were located on the internal
storage while the database VM’s vmdk files utilized either
FlashSystem 840 or the baseline HDD storage system,
depending upon the test.
Hardware
IBM System x3850 X5
●● Four Intel Xeon X7560 processors, 2.27 GHz
●● 256 GB RAM
16 Gb storage area network (SAN) switch
FlashSystem 840
●● Four 8 Gbps active Fibre Channel ports
●● 12 flash modules
●● 18.75 TB usable capacity
Baseline HDD storage system
●● 44 x 15k Fibre Channel disk drives
●● Four spare 15k Fibre Channel disk drives
●● 5.44 TB usable capacity
●● 2 GB cache
●● Four 4 Gbps active Fibre Channel ports
Software
●● Microsoft Windows Server 2008
●● Microsoft SQL Server 2008 R2 SP2
●● VMware ESXi 5.5
●● DVD Store 2.1
Performance tuning
For the test configuration, IBM also applied the following tun-
ing to help optimize performance of the FlashSystem 840 stor-
age system, baseline HDD storage system and VMware ESXi
virtual machines.

5. 5
Technical White Paper
May 2014IBM Systems and Technology
FlashSystem 840 tuning
●● VMware multipathing policy: Round robin
●● VMware round-robin configuration: IOPS value set to 4
●● Array configuration: Single RAID 5 across all modules
●● Volume configuration: Seven 1.5 TB volumes
Baseline HDD storage system tuning
●● VMware multipathing policy: Most recently used (MRU)
●● VMware multipathing configuration: Dedicated path and
port assigned for each data store
●● Array configuration: Four RAID 5 arrays with 11 x 15k
Fibre Channel disks each
●● Volume configuration: Four 1.3 TB volumes
VMware tuning: Database virtual machines
●● vCPU: Four
●● RAM: 24 GB
●● SQL memory: 1 GB
●● Database size: 550 GB
●● Total database files size: 850 GB
VMware tuning: Driver virtual machines
●● vCPU: Two
●● RAM: 24 GB
Database performance tests
To test the performance of a business-critical workload on
FlashSystem, IBM used the DVD Store test application,
which simulates a middleware database responding to web
users browsing and ordering DVDs. To reflect the range of
user traffic that may occur, one or more database replicas
can be defined, and one or more threads of work may be
launched on each replica. Each thread proceeds independently,
producing requests for service. The stream of work within a
given thread may often contain a sequence of logically related
requests (for example, a specific user may first search for a
DVD and then purchase that DVD).
The most important database metrics for the DVD Store test
are the total volume of database transactions (measured in
operations per minute) and the average transaction response
time. In addition, IBM examined how the average transaction
response time may change, based on different operating
conditions.
IBM tested the effectiveness of each storage solution by using
most of the capacity to store replicas of the test database and
then concurrently running a selected number of threads on
every replica—that is, one thread running per database, two
threads per database and so forth. To assess the full range of
potential operating conditions, the number of threads launched
per database varied by up to several dozen.
Although IBM used four database replicas for the baseline
HDD storage system, seven replicas were used for the
FlashSystem storage array, partly due to the different capacities
that were available and partly due to the higher overall
throughput obtained with the FlashSystem 840 storage. To
take full advantage of the high FlashSystem 840 throughput,
IBM deployed a larger number of database replicas for that
storage system.
Performance analysis: Transaction
throughput and response time
Do the low latencies provided by FlashSystem technology
translate to a better end-user experience? That’s what the
IBM performance tests hoped to find out. As presented in
Figure 1, the test results showed dramatic improvements in
transaction throughput and response time for users of the
DVD Store application on FlashSystem 840, when compared
to the traditional HDD system.

6. 6
Technical White Paper
May 2014IBM Systems and Technology
Figure 1. DVD Store application running on FlashSystem 840 compared to a
traditional HDD storage system
Transaction performance analysis
Database transaction
throughput improved by
4 times with little change
in response time
1,200
1,000
800
600
400
200
0
0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000
Orders per minute
Traditional disk storage system IBM FlashSystem 840
Databasetransactiontime(ms)
To appreciate the performance results shown in Figure 1, con-
sider a production environment that needs to support a specific
workload. Since IT staff must plan for unexpected peak loads
and provide room for future growth, the normal operating load
would not typically reach the maximum levels shown in our
chart. Instead, the production environment would tend to stay
in the range of throughputs that are less than, for example, two
thirds of the maximum. In that range, the transaction response
times delivered by FlashSystem 840 barely change—in fact,
they are so fast that responses would appear to be instantaneous
to users. The response times are consistently less than 50 milli-
seconds (that is, less than 1/20 of one second).
By contrast, the transaction response times delivered by the
HDD-based solution tended to vary significantly, depending
upon the time of day or other business conditions affecting the
transaction volume. Also, the transaction response times
achieved by the system could be easily perceived as delays from
the user’s point of view (significant fractions of one second).
A frequent user of the application could experience noticeable
but minor delays, interspersed with longer delays that might
be perceived as irritating.
In the context of a web-based retail application, IBM perfor-
mance results showed that the use of FlashSystem storage can
help improve the overall user experience. This improvement
may, in turn, lead to a competitive business advantage.
Performance analysis: CPU utilization
The test results also showed that using FlashSystem storage
can help reduce the host processing required for a web retail
application such as DVD Store. Figure 2 shows the CPU
utilization rates when running the DVD Store database on
both FlashSystem 840 and the baseline HDD storage system.
It compares the utilization rates for both light and heavy data-
base loads, using either one or 10 threads per database replica.
The faster I/O processing of the FlashSystem 840 database
led to a sharp reduction in the CPU utilization per unit of
transaction volume. For both light and heavy loads, the
CPU utilization dropped by more than a factor of two.

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Technical White Paper
May 2014IBM Systems and Technology
Average CPU utilization per 5,000 orders
per minute
30
25
20
15
10
5
0
Low I/O intensity High I/O intensity
Databaseutilization(%)
Traditional hard disk system IBM FlashSystem 840
Figure 2. CPU utilization at 5,000 orders per minute
By reducing the host processing requirements, FlashSystem 840
can also enable larger volumes of work to run on a given physi-
cal system. This, in turn, can lead to significant reductions in
the overall cost of delivering an application.
Conclusion
The high I/O throughput and consistent, low latency of
FlashSystem 840 provides value on many levels. The high
throughput allows organizations to scale their applications as
demand increases. At the same time, the consistently low
latency enables applications to scale without negatively
impacting the end-user experience.
In addition to improving the end-user response time—and cus-
tomer experience—the low latency of FlashSystem 840 can
reduce overall CPU utilization. As a result, organizations gain
flexibility. For example, IT staff can reserve the unused CPU
cycles for scaling of the application; or, in a virtualized environ-
ment, they can use the extra CPU cycles for other virtual
machines, thus improving overall VM density.
One of the key business cases for a virtualized environment is
improved infrastructure utilization. IBM performance tests
show that using low-latency storage with heavy I/O workloads
can significantly reduce CPU utilization. These savings, when
spread across many virtual hosts, can help to either reduce the
size or quantity of hosts required or allow for greater density
and thus a higher utilization of each host.
As organizations move toward deploying top-tier workloads
in virtualized environments, these workloads require high
performance from every component, including the storage
systems. IBM used the DVD Store benchmark to simulate this
type of top-tier workload. When pairing FlashSystem 840 with
the DVD Store application in a VMware environment,
organizations can achieve extreme high performance and low
latency—far more than with an HDD storage system. The
result is higher capacity to meet future needs, a better user
experience and optimized IT costs for maximum return.

8. For more information
To learn more about IBM FlashSystem storage, please contact
your IBM representative or IBM Business Partner, or visit:
ibm.com/systems/storage/flash/
For more information about other topics covered in this paper,
please visit:
●● IBM Systems on IBM PartnerWorld®—
ibm.com/partnerworld/systems
●● IBM Redbooks—ibm.com/redbooks
●● IBM Publications Center—www.elink.ibmlink.ibm.com/public/
applications/publications/cgibin/pbi.cgi?CTY=US
●● VMware Product Documentation—
www.vmware.com/support/pubs/
●● VMware VMmark 2.x Documentation—
www.vmware.com/products/vmmark/
●● Dell DVD Store Benchmark—linux.dell.com/dvdstore/
Additionally, IBM Global Financing can help you acquire the
IT solutions that your business needs in the most cost-effective
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ness goals, enable effective cash management, and improve your
total cost of ownership. IBM Global Financing is your smartest
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forward. For more information, visit: ibm.com/financing
© Copyright IBM Corporation 2014
IBM Corporation
Systems and Technology Group
Route 100
Somers, NY 10589
Produced in the United States of America
May 2014
IBM, the IBM logo, ibm.com, FlashSystem, FlashCopy, PartnerWorld,
Real-time Compression, and System x are trademarks of International
Business Machines Corp., registered in many jurisdictions worldwide.
Other product and service names might be trademarks of IBM or other
companies. A current list of IBM trademarks is available on the web at
“Copyright and trademark information” at ibm.com/legal/copytrade.shtml
Intel and Intel Xeon are trademarks or registered trademarks of Intel
Corporation or its subsidiaries in the United States and other countries.
Linux is a registered trademark of Linus Torvalds in the United States,
other countries, or both.
Microsoft and Windows are trademarks of Microsoft Corporation in the
United States, other countries, or both.
This document is current as of the initial date of publication and may be
changed by IBM at any time.
The performance data discussed herein is presented as derived under
specific operating conditions. Actual results may vary.
THE INFORMATION IN THIS DOCUMENT IS PROVIDED
“AS IS” WITHOUT ANY WARRANTY, EXPRESS OR
IMPLIED, INCLUDING WITHOUT ANY WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE AND ANY WARRANTY OR CONDITION OF
NON-INFRINGEMENT. IBM products are warranted according to the
terms and conditions of the agreements under which they are provided.
VMware vSphere ESXi and VMware VMmark are not IBM products
or offerings. VMware vSphere ESXi and VMware VMmark are sold or
licensed, as the case may be, to users under VMware’s terms and conditions,
which are provided with the product or offering. Availability, and any
and all warranties, services and support for VMware software is the direct
responsibility of, and is provided directly to users by, VMware. DVD
Store is not an IBM product or offering. DVD Store is an open-source
application hosted by Dell. Availability, and any and all warranties, services
and support for DVD Store is the direct responsibility of, and is provided
directly to users by, Dell.
Actual available storage capacity may be reported for both uncompressed
and compressed data and will vary and may be less than stated.
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