There are quite a few reasons to deploy storage systems,1
especially for the systems in a mySAP landscape. Beyond consolidation
of storage demands of multiple hosts for more efficient storage management
and higher availability, you also gain special features, such as non-impact
backup, fast recovery, consistent online copies of an entire mySAP landscape,2
and remote data vaulting for preparation in disaster failover scenarios.3
But when it comes to monitoring
your landscape, storage systems are just like any other component needed
to run business processes in mySAP Business Suite — they need monitoring
for performance issues. To quickly and effectively analyze and address
issues, system administrators need to be alerted when a performance indicator
for a component has exceeded its preset threshold.
Administrators of an SAP landscape already
have the ability to monitor SAP, OS, and DB components through SAP’s
monitoring suite, the Computing Center Management System (CCMS), and its
CCMS Alert Monitor console. Storage vendors also provide their own set
of sophisticated tools specifically for monitoring storage systems. But
for most storage systems, there has not been a clear integration path
to bring all this information together in this single monitor for a convenient,
“one-stop” look at performance across the landscape —
This article will introduce some ongoing
work, in cooperation with our storage partners, to extend available storage
system monitoring capabilities into SAP’s CCMS. This includes new
“data suppliers” from vendors that allow CCMS to present this
information. But first, let’s review some of the current challenges
for monitoring data transfer and performance and how the CCMS monitoring
infrastructure helps ease this process.
The Challenge of I/O Performance Analysis
To effectively prevent, identify, and correct performance troublespots,
you have to cover a lot of territory. Data transfer issues can occur at
any number of points along the “I/O stack”:
- On the application level, these holdups may be caused
by wasteful I/O operations due to non-optimal program code or missing
- On the database level, buffers may be improperly
configured and files may be laid out in a way that leads to conflicts
during access of multiple concurrently running tasks.
- Due to an inappropriate layout of file systems and logical volumes
on the operating system level, database files may be
crowded onto a few physical volumes (or worse, a single volume).
- The throughput of the network may be insufficient
if the reserved paths from the host to the storage system are overutilized,
or if switches are used by too many hosts.
- On the storage system level, single components such
as host adapters, cache, disk adapters, physical disks, or the connections
between these components may be overutilized. Where there is no evident
malfunction of one of these components, I/O issues at this level can
usually be solved by distributing database files on as many physical
disks as possible.
While the fixes to these slowdowns can
be straightforward, pinpointing the weak link and analyzing all these
issues involves expert knowledge of all components along the I/O stack.
The complexity of an I/O analysis increases with the possible combinations
of SAP applications and heterogeneous DB, OS, and storage systems that
make up a mySAP landscape.
Monitoring Your SAP Landscape with CCMS
Since it is nearly impossible to monitor all components of all systems
regularly, SAP has integrated monitors for applications as well as supported
DB and operating systems into the Computing Center Management System (CCMS).
CCMS uses monitor objects
(e.g., “DB response time”) to track the values recorded by
data suppliers, tools for data collection that are provided
by each external component. CCMS then displays an alert when a certain
threshold exceeds or falls below a specified value. This is displayed
as a tree structure of systems, along with their monitors and alerts,
in the CCMS Alert Monitor.
Along with the Alert Monitor, SAP delivers
a large selection of predefined monitors that contribute to a significant
reduction in the system administration workload. Beyond this, CCMS is
the data collector for the Solution Manager, SAP’s standard portal
for providing customer support and services.
Integration with SAP CCMS
So how do you integrate your storage system information into
All storage vendors already offer sophisticated
tools that allow their customers to monitor almost every single detail
of the storage infrastructure. Customers generally use these tools for
their productive storage infrastructure.
The tools of the various vendors are similar
in design. For data collection, storage system software provides a server
that uses an API to gather data either directly, from the storage system
itself, or indirectly, from a database that is updated by a regularly
To standardize this API, some vendors recently started initiatives
to provide a common interface for all the various types of storage
systems they offer. They also plan to extend their API for storage
systems from competing vendors.
In order to close the storage- monitoring gap in SAP systems and move
collected data into CCMS, you’ll need another tool — the storage
system’s data supplier.
SAP’s Interface to External Monitors
As with the OS and DB components, a data supplier must be implemented
to provide the storage system information to CCMS. An SAP API acts as
the interface between CCMS and the data supplier tool. Currently, SAP
provides these APIs for Java and for the C programming language.
A data supplier should run on UNIX and
Windows NT operating systems, either together with an SAP system on the
same host or on a separate host, in case demands on system resources increase.
Let’s see how this would work in
practice. Figure 1 depicts the integration of storage
system information into the SAP monitoring infrastructure.
|mySAP Landscape with Storage Systems
Here we have a mySAP landscape composed
of three servers and four storage systems (the gray and blue storage systems
indicate systems from different vendors). The servers are devoted to SAP
R/3, SAP CRM, and SAP BW, and data from these systems is distributed across
the storage systems. The R/3 system is the Central Monitoring System (CEN),
which gathers the information from all systems and is the source for the
CCMS Alert Monitor.
Beyond pure storage system information, a CCMS integrated monitor
shows how the database objects (tables, indexes, temp spaces, and
LOGs) are mapped to the physical layer (disk adapter, physical disks)
of the storage system.
Advantages of Integrating Storage System
Information into the CCMS
administrators will gain access to storage information within their
SAP central monitoring system.
the integration of storage information into SAP’s
monitoring infrastructure, a deviation
of storage key performance indicators
(KPIs) from specified values can automatically
lead to an alert.
information needed in order to analyze the entire I/O stack is available
in a single system. This especially eases analysis of the database
layout and simplifies the usually time-consuming task of mapping
database objects to the physical layer.
an integrated CCMS Alert Monitor, you’ll have support for
your storage systems from SAP service staff, who can analyze storage
system-related I/O issues remotely, right from your Alert Monitor.
Remember that the server involved in the
data collection process accesses storage system data in one of two ways:
- Directly from the storage system — Here, a
server that is connected to the storage systems is needed on each host
1a. A client will collect the information provided
by the servers and transfer it to the data supplier 2a.
- From a separate database — In this case, a
vendor-specific collector must regularly update the database 1b.
The server reads the data from the database and transfers all requested
data to the data supplier 2b.
The data supplier that delivers the storage
information to CCMS deploys the SAP-provided API and writes the information
into shared memory 3.
The CCMS agents transfer the data from
shared memory to the central monitoring system (CEN) using SAP RFC4
4. As RFC servers, the agents allow the CEN to request
information (pull technology). As RFC clients, the agents send information
to the CEN independently (push technology). This improves performance,
as the CEN no longer needs to periodically query the agents.
The storage system’s data supplier program is OS-dependent.
Each storage vendor should deliver a data supplier for all operating
system platforms — or at least for the most common platforms.
For More Information
For more information on those storage system vendors that are currently
working on CCMS integration and those that have already realized CCMS
integration, visit http://service.sap.com/atg
under “Storage Monitoring.”
1 By storage system,
I mean a dedicated computer with special-purpose disk storage management
functions, specifically designed to consolidate the storage demands of
2 See "Create a Consistent Copy of Your Entire
SAP Landscape Without Taking Systems Offline" in the July-September 2003
SAP Insider (www.SAPinsider.com).
3 See "How Storage Helps Reduce the Total
Cost of Ownership for mySAP Solutions" in the January-March 2003 SAP
4 Remote Function Call.
Siegfried Schmidt joined SAP in April 1989, developing SAP’s
interfaces to database platforms. In 1997, he became a member of the Advanced
Technology Group — a department in SAP’s support organization.
In selected projects, he supported customers and the R/3 development team
in optimizing mission-critical processes and performance. Currently, he
develops, in cooperation with manufacturers of storage subsystems, infrastructure
concepts and solutions that meet customers’ requirements of system
availability, ease of administration, and performance.