HP XP P9500 Storage - Manual (Page 6)

1 External Storage Access Manager overview
Unless otherwise specified, the term P9000 in this guide refers to the following disk array:
•
P9500 Disk Array
The GUI illustrations in this guide were created using a Windows computer with the Internet Explorer
browser. Actual windows may differ depending on the operating system and browser used. GUI
contents also vary with licensed program products, storage system models, and firmware versions.
External Storage Access Manager (ESAM) enables host-based applications to fail over between
P9500 (P9500) storage systems in the event of an I/O failure to the primary storage system.
Because of the way ESAM is configured, failover is accomplished without restarting the application.
This guide provides instructions for planning, implementing, operating, maintaining, and
troubleshooting an ESAM system. Procedures for disaster recovery are also included.
Resources that can be executed for each function
Remote Web Console secondary window shows all the resources in the storage system. However,
the functions described in this manual are only available to the resources that are assigned to a
user account who logs into the Remote Web Console. Verify the resource group ID in the Report
Display dialog boxes, and then execute the operations for the resources assigned to the user
account. When you use the functions, the resources for each operation must satisfy the specific
conditions.
For details on user accounts, see the HP P9000 Remote Web Console User Guide. For details on
the conditions of the resources, see the HP P9000 Provisioning for Open Systems User Guide or
the HP P9000 Provisioning for Mainframe Systems User Guide.
How ESAM works
ESAM uses Continuous Access Synchronous software to create a synchronous remote copy of a
production volume. But where Continuous Access Synchronous is suited to large-scale disaster
recovery, ESAM is intended for recovery from on-sight disasters such as power supply failure.
Because of this, ESAM is configured differently than a typical Continuous Access Synchronous
configuration.
•
The ESAM primary and secondary storage systems are connected to the same host. When
an ESAM pair is created, the host sees the primary and secondary volumes as the same
volume.
•
ESAM requires multipath software to be installed on the host. In the event that the host cannot
access the production volume on the primary storage system, host I/O is redirected via the
host multipath software to the secondary volume on the remote system. Failover is accomplished
without stopping and restarting the application.
6 External Storage Access Manager overview