Compaq 108164-003 - ProLiant - 800 White Paper page 22

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The log volume must always be fault tolerant. Due to the sequential write-only nature of the
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log volume, many disks in a RAID set to not provide a significant benefit. Two high capacity
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. . disks mirrored (RAID 1) is a configuration that provides good sequential write performance
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and excellent fault tolerance. Note that the IS buffer has nothing to do with log volume
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performance.
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In most cases there is no performance degradation imposed by turning off the SMART
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Controller Array Accelerator cache on the Log volume. Leave it enabled on the database
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Store (IS) volume.
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System Memory
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128 Mbytes of RAM is a good amount of system memory to start with for the 500 user range.
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256 Mbytes can provide additional benefit.
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Monitor the available memory on the system using NT Performance Monitor. If there is
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unused memory available on a consistent basis, allocate a portion of it to the IS buffers.
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However, do not over-allocate RAM. There should be at least 10-15 Mbytes free memory in
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the system at all times.
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Increasing RAM in the system and allocating it to the IS buffer can significantly improve
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client response time. In some cases, doing this may be more cost effective than adding disks
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to the drive subsystem.
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General
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Based on the tests profiles used for purposes of this paper, the maximum practical number of
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users for a single Exchange Server is 1500. Depending upon your user load, that is most
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likely a worst case scenario. Results will vary with different cases.
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Always run Exchange Optimizer after the initial setup of Exchange Server. Also run it after
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changing configuration of the server.
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