HP/SAP SAN Storage White Paper

SAP

executive summary

SAP is typically deployed in components starting with core R/3 and then expanding into other components like business warehouse and supply chain management. Because of this evolution it is likely that our data centers have a series of servers directly connected to private storage or multiple servers connected to a centralized storage component. Either of these configurations places a heavy manpower load on IT for management and business-continuation processes such as backup and database duplication. Additional issues occur with the exponential growth of storage requirements and the need to improve operational efficiency. Storage consolidation provides the answer. However, storage vendors must provide SAP installations with highly available, high-performance, scalable storage. Enterprise storage, combined with a storage area network (SAN), solves today's problem of the increasing cost and difficulty of storing and managing data. Centralized storage and SANs deliver storage efficiency through:

• increased capacity utilization by consolidating disk and tape resources across multiple servers
• multiple paths to the same storage, resulting in high availability
• lower storage-management costs as a result of centralized management
• improved backup/restore windows and reduced LAN congestion by removing backup traffic from the LAN and placing it on the SAN

The HP SAN is able to deliver storage efficiency regardless of the customer's environment by offering the broadest range of SAN components-ranging from entry/midrange virtual arrays to enterprise-class XP arrays. All SAN solutions are supported by HP OpenView Storage Area Manager (SAM) software and HP services, consulting, and support.

introduction
The purpose of this document is to discuss the evolution of storage in the data center-especially in the SAP environment- and to recommend migrating to a storage SAN. This paper reviews the various configurations that data center storage might be in, including direct-attached storage (DAS) and centralized attached storage (CAS), and describes the design and benefits of a storage SAN architecture. This document clearly demonstrates the benefits that a SAN plus OpenView and Omniback software can bring to a real-life storage problem.

the storage efficiency problem
The amount of data stored by SAP customers is growing exponentially. Customers who started with core R/3 implementations typically have hundreds of gigabytes of data online. As they leverage their core R/3 investment and add modules like business warehouse, supply chain management, and customer relationship management, they see a dramatic rise in the amount of online data requiring management. This data-storage problem is fueled by the need for 24x7 operations and limited amounts of downtime. In fact, research shows that more data will be generated in the next three years than in the last 40,000 years (UC Berkeley). Drivers of this explosive growth include manufacturing, online government services, digitized x-rays, e-mail and the increasing richness of attachments, and the need to turn data into information a business can use.

Storing, managing, and protecting this data is becoming difficult and costly for organizations of all sizes. Buying and adding sufficient disk capacity to cope with application growth; finding, training, and retaining staff to manage storage; and having sufficient time to back up critical data are all issues forcing IT departments to reconsider their storage architecture.

A SAN can bring instant ROI by addressing the problems of storing, managing, and protecting data in a growing environment. Many analysts point to the benefit of networked storage as compared to direct-attached storage.

networked storage is about 55-60% less expensive than the same-sized DAS environment (based on a 2 TB system)₁.

Specifically, SANs improve capacity utilization, reduce storage resource management costs through centralization, and remove backup traffic from the LAN. Reality Research indicates that the average ROI for SAN investments is 58 percent (compared to 34 percent for network-attached storage [NAS] investments).

capacity utilization

• reduce waste by improving capacity utilization from 40-50% in a DAS environment to 80% with a SAN
• defer capacity increases and benefit from an annual 40% decline in disk/tape costs

In an SAP DAS environment, each server has a dedicated storage array and backup device, each of which is specified with excess capacity ('white space') to allow for future storage growth. In reality, much of this additional capacity is unused, but IT managers prefer to have the excess capacity because adding additional storage to disparate groups of DAS devices is time consuming. Typically, capacity utilization in a DAS environment runs at 40-50 percent.

In a SAP CAS environment servers are networked to centralized storage devices. This provides the customer with benefits from centralized storage, but they have the same capacity issues. Storage additions need to be made individually for each server, and allocation on the centralized storage device needs to be handled on an application-by-application basis.

figure 1: direct-attached storage

This figure shows independent islands of DAS, each managed individually. In the event that one server runs out of storage space, capacity from another server cannot be used.

In an SAP CAS environment, multiple servers are direct-attached to a centralized storage unit. Backups can be done by an individual server or integrated into a dedicated backup server, or a combination of both.

The centralized storage unit can have pockets of excess capacity, but this available space is not easily allocated between applications. In reality, much of this additional capacity is unused, but IT managers prefer to have the excess capacity in place. Storage managers are still required to manage storage by centralized unit, and it requires a complex process to allocate new storage to an individual application.

figure 2: centralized attached storage
This figure shows centralized storage directly connected to multiple hosts, each managed individually.

In an SAP SAN structure, storage is pooled across multiple hosts and operating environments as well as backup devices. Using SAN management software such as HP OpenView SAM, the host can be allocated more LUNs/capacity from the common central storage resource, and more storage can be added or utilized by interconnecting it to a switch.

HP OpenView SAM manages multivendor storage across distributed environments. HP OpenView SAM components include:

• hp OpenView storage node manager-provides centralized management for SANs
• hp OpenView storage allocater-delivers storage assignment when and where it is needed
• hp OpenView storage builder-provides a view of storage allocation and usage
• hp OpenView storage optimizer-monitors all SAN components
• hp OpenView storage accountant-provides storage metering for financial analysis and charge-back

the solutions approach
Following are two SAN configurations that deliver the storage-efficiency benefits mentioned previously.

entry-level SAN
This entry-level SAN configuration is ideal if you are taking your first step away from a DAS or CAS environment. At this stage, you have a proliferation of servers and are managing storage individually by application and server whether in the DAS or CAS mode. You may not be ready for a system consolidation, but you do want to maximize your storage investment. The entry-level SAN provides high availability, a network-attached tape library for backups, and improved bandwidth on your critical SAP LAN. It introduces multiple Fibre Channel (FC) switches and a centralized tape library, and it allows for multiple host access to both disk and tape. This allows for ease in backing up, archiving, and managing data, and introduces the benefits of the SAN architecture.

figure 3: a medium-sized deployment of SAP with a SAN

enterprise SAP SAN
This full enterprise-level SAN includes XP and high-end tape. You may be a candidate for this solution if you already have centralized storage (as in the CAS model) or you want to centralize your storage and tape capabilities. Or you may be looking at system consolidation of your SAP environment to reduce server proliferation. Perhaps you have other servers as part of your SAP environment, or you have other environments that you want to bundle into your overall SAN architecture. Essentially, you are making a strategic decision about the management of your data center and are likely to be interested in the high-availability blueprints.

figure 4: an enterprise deployment of SAP with system consolidation, disaster recovery, and SAN

Moving to a SAN allows storage for multiple servers to be pooled into one physical or logical unit. All white space is also pooled and, as a result, less excess capacity is actually needed because each server can request additional capacity from the central pool as needed. In other words, pooled storage can be shared among servers on the network. Typically, in a SAN environment, capacity utilization runs at 80 percent.

As you expand your SAP environment, future capacity increases can be deferred and IT departments can benefit more readily from the annual 40-percent decrease in disk/tape costs. Many long-time SAP customers are now looking for and implementing archiving solutions for their environments. Archiving data to SAN-attached libraries is easier to accomplish. Instead of adding spare capacity for each server in advance and watching each server's storage demands grow at varying rates, overall capacity growth can be smoothed out and new capacity added in a more gradual, logical manner.

SAN efficiencies and capabilities
centralized management

• manage 10 times your current storage environment through a single management console. These include OpenView, the OpenView SAP Smart Plug-in, and Omniback's Zero Downtime Backup for SAP and Instant Restore for SAP
• have a coherent picture of your total storage pool
• allocate storage resources and server resources with

OpenView SAM tools

The cost savings SANs bring from improved capacity utilization are impressive. However, the greatest savings come from reduced people costs because SANs greatly simplify storage management. 'In a distributed environment, the real cost of storage is not in the hardware, but primarily in the labor involved in managing storage and in productivity lost due to network outages.' A combined study by Merrill Lynch & Co. and McKinsey & Company highlights the dramatic differences in total cost of ownership (TCO) of DAS versus SAN: DAS costs $0.84/MB and SAN costs $0.38/MB (see figure 5).

figure 5: TCO comparison

As shown in figure 6, people costs represent the greatest part of the overall cost of a DAS environment. For 50 GB of storage, the 3-year people costs are as follows:

figure 6: 3-year people costs

The $1.7 million savings may seem high, but if you consider the average cost of an IT administrator as $160k per year, the $1.7 million 3-year savings represents 3.6 fewer administrators needed for 50 GB of SAN storage compared to 50 GB of DAS.

Finally, IT managers are better able to understand what their total capacity is and what their utilization and growth rates are by consolidating storage into one physical or logical pool. Multiple islands of DAS tend to make knowledge of the overall storage environment difficult. 'We have a ton of DAS distributed all over the place, but it's difficult to have an accurate sense of our total capacity, capacity utilization, or performance at any one time.' IT managers with CAS environments have similar problems-even though they have more control over their centralized storage frames-and will benefit from the move to SAN.

scalability options
These base configurations can be scaled in the following ways:

• more switches
• more hosts
• more storage arrays
• a wider selection of operating systems, without using

OpenView SAM
SAN backup

• pool backup devices
• reduce the bandwidth burden on your LAN with LAN-free backup

Just as disk capacity can be pooled and shared among all hosts on the SAN, backup devices can also be shared. Instead of having a tape device attached to each storage array and server, a single large tape library can be used to back up the entire SAN. This is a more efficient use of capacity.

Businesses are finding that their LANs are becoming more saturated because of the increasing quantity and richness of data generated. As a result, LAN performance slows and users complain to their IT managers about increasing service times for their SAP transactions. In an SAP SAN environment, reduction of LAN traffic allows more bandwidth to send critical data from application servers to database servers and end users.

Your SAP SAN environment allows you to remove the client LAN from the backup process by allowing the server, the storage, and the backup device to communicate directly and transfer backup data over the SAN. This removes traffic from the LAN and frees up the server from processing multiple LAN commands.

storage efficiency: benefits summary
The storage efficiency benefits a SAN brings can be split into 'hard' ROI and 'soft' benefits.
hard ROI

• increased capacity utilization-disk and tape
• reduced management cost-manage more capacity with the same number of, or fewer, people

soft benefits

• a coherent view of your total storage pool and simplified planning
• reduced LAN congestion through removing backup traffic from the messaging network
• disaster avoidance, because a SAN allows you to more easily implement a high-availability environmcent and avoid costs of downtime; see the high-availability blueprint for further details

SAN efficiency: benefits summary
The benefits of moving from a DAS or CAS environment to a SAN are many. You increase operational, capacity, and utilization efficiencies and reduce LAN traffic, and you can utilize your resources more efficiently to manage your business. In addition, you gain the ability to manage storage at an enterprise level rather than a per application or per server basis. And you can use a single storage device-disk or tape-to support multiple applications and servers. Incorporating a SAN environment into your data center provides you with an unparalleled opportunity to manage your data instead of letting your data manage you!

additional information
SAN solutions
Additional HP SAN Solution business blueprints: high availability.

For technical information on implementing the SAN configurations outlined in our business-level blueprints, see our SAN solution technical blueprints at www.hp.com/products1/storage/san/index.html. SAN solution technical blueprints include entry-level SAN, entry-level high-availability SAN, enterprise SAN, and enterprise high-availability SAN.

For answers to further SAN implementation questions, contact an HP sales representative, who will be able to consult our regularly updated SAN interoperability matrices and provide guidance on additional OS, fabric topology, and third-party and legacy-device interoperability.

hp SAN components
To get further information on the individual components in an HP SAN, go to www.hp.com/go/storage

hp SAN management components
See www.hp.com/products1/storage/disk_arrays/highend/xpsolutions/index.html for descriptions of the HP Business Copy (mirroring), Continuous Access (remote mirroring), and Zero Downtime Backup solutions for the XP array family.

hp SAP-specific components

• Somersault-HP worked with SAP to develop Somersault to eliminate the failure of the Enqueue Service. It is available for both HP-UX and Windows.
• E-Xsid-Provides for automated SAP system/database copies for quality assurance and development. The tool not only copies the data but also is integrated into SAP and alters the system ID and the system number.
• System Performance Analysis for SAP (SPAS)-A complete solution that provides XP performance and configuration data into SAP's Cluster Consistency Monitor Services (CCMS) central console. The solution includes product, installation, configuration, and training.
• CCMON-Monitors and alerts on the consistency of the high-availability clusters. It periodically checks the clusters and automatically alerts you of any changes or inconsistencies found in the environment.
• HP MC/Serviceguard Extensions for SAP-Extends MC/Serviceguard's failover capabilities for SAP R/3 with scripts built in to speed implementation, standardization, and ROI.
• HP OpenView data management software-Provides excellent backup strategies for SAP environments. It is available with integrated links to SAP's BRBACKUP and BRARCHIVE.
• HP OpenView Plug-ins for R/3-An HP-developed plug-in for SAP customers that extends the management of SAP and provides more than 100 preconfigured reports from SAP.
• HP OpenView Business Transaction Observer (BTO)-HP-developed product that allows you to manage your service-level agreements (SLAs) for your SAP system by providing high-level and drill-down views of response times to help you identify bottlenecks.

hp services
HP offers a complete lifecycle of SAN support and consultancy services; go to www.hp.com/hps/storage for full details. Specific SAN services that may be of interest to customers looking into our Storage efficiency blueprints are:

• performance and capacity planning services-We will analyze the performance and capacity usage of your storage environment, including all major system components. You will receive a detailed performance and capacity report with recommendations on how to tune your performance and optimize your capacity usage.
• data migration services-We offer a stress-free data migration from mission-critical HP-UX, Windows NT/2000, Sun legacy, and EMC storage systems to the HP StorageWorks SAN platform, based on an end-to-end management of the entire data-migration process.
• storage/SAN integration services-HP also offers storage/SAN integration services, which provide a trouble-free and quick onsite installation of your SAN solution.

For full details, see www.hp.com/hps/gds

Hewlett-Packard Company