Product Overview
The SAN Spare Disk Manager is a highly cost-effective RAID-1 management automation tool that improves the capabilities of disk mirroring by enabling a system administrator to establish a spare-disk pool and by automating various aspects of failed mirror replacement.
You can use the SAN Spare Disk Manager with the MCP Mirrored Disk feature. Mirrored Disk increases disk subsystem availability and integrity by maintaining two, three, or four copies of selected disk units to provide protection against disk failures. Mirrored Disk provides a capability that is often referred to as RAID-1.
With the SAN Spare Disk Manager, a system administrator initially establishes a spare-disk pool whose members are designated for use as mirror replacements. Subsequently, if a mirror is removed from its online set because of failure, this pool is programmatically searched for a compatible disk. When one is found, a new mirror is created without any operator intervention. The spare-disk pool can include in-use spares, which are normally members of other mirrored sets but can be removed if needed elsewhere.
General Features
SAN Spare Disk Manager eliminates the need to have operators with detailed knowledge of the disk subsystem configuration available to perform these unplanned tasks.
As with Mirrored Disk, the SAN Spare Disk Manager is totally transparent to application programs and end users. All you need are the extra disk units that are to be used as mirrors and the spare-disk pool.
The SAN Spare Disk Manager consists of two separate components:
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One component resides in the Master Control Program (MCP) and is responsible for establishing and maintaining the spare-disk pool, detecting that a mirror has failed, and selecting a replacement candidate from the pool. This component is activated when the SAN Spare Disk Manager run-time key is resident on the ClearPath server.
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The other component resides in a supervisor program. This program is responsible for determining if and when a failed mirror is actually replaced. Two supervisor program options are available, depending on which products you license:
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If you license both the System Assistant product and the SAN Spare Disk Manager, you should use the standard System Assistant supervisor program to manage replacement of failed mirrors. The SAN Spare Disk Manager includes a sample System Assistant script that can help you write a customized script. For example, you can write a script so that only selected mirrored sets are eligible for replacement. In addition, your script can specify that replacement be deferred to a time when system use is lower. This flexibility can be important because the creation of a mirror consumes significant system resources, particularly on smaller systems.
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If you license only the SAN Spare Disk Manager and do not license System Assistant, you should use the SYSTEM/MDPF/ASSISTANT supervisor program included in the SAN Spare Disk Manager. This program automatically and without operator intervention replaces any failed mirror as soon as it detects the failure.
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Ordering Information
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Platform |
Style |
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ClearPath |
The ordering style for the SAN Spare Disk Manager is VSS nn-SSM, where nn represents performance groups 10 through 160 (in increments of 10). |
Source code is not available for this product.
Product Information
Refer to the following documents for more information:
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System Operations Guide (8600 0387)
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System Assistant Operations and Programming Guide (8600 0825)
