Dell PowerVault MD3260i - Manual (Page 297)

Additional Information
When you use this command, you can specify one or more of the optional parameters.
Auto Support Data
When enabled, the set storageArray autoSupportConfig command causes all configuration and state
information for the storage array to be returned each time a critical Major Event Log (MEL) event is detected. The
configuration and state information is returned in the form of an object graph. The object graph contains all relevant
logical and physical objects and their associated state information for the storage array.
The set storageArray autoSupportConfig command collects configuration and state information in this
way:
• Automatic collection of the configuration and state information occurs every 72 hours. The configuration and
state information is saved to the storage array zip archive file. The archive file has a time stamp that is used to
manage the archive files.
• Two storage array zip archive files are maintained for each storage array. The zip archive files are kept on a
physical disk. After the 72-hour time period is exceeded, the oldest archive file is always overwritten during the
new cycle.
• After you enable automatic collection of the configuration and state information using this command, an initial
collection of information starts. Collecting information after the you issue the command makes sure that one
archive file is available and starts the time stamp cycle.
You can run the set storageArray autoSupportConfig command on more than one storage array.
Cache Block Size
When you define cache block sizes, use the 4-KB cache block size for storage arrays that require I/O streams that are
typically small and random. Use the 8- KB cache block size when the majority of your I/O streams are larger than 4 KB
but smaller than 8 KB. Use the 16-KB cache block size or the 32-KB cache block size for storage arrays that require large
data transfer, sequential, or high-bandwidth applications.
The cacheBlockSize parameter defines the supported cache block size for all of the virtual disks in the storage
array. Not all RAID controller module types support all cache block sizes. For redundant configurations, this parameter
includes all of the virtual disks that are owned by both RAID controller modules within the storage array.
Cache Flush Start and Cache Flush Stop
When you define values to start a cache flush, a value that is too low increases the chance that data needed for a host
read is not in the cache. A low value also increases the number of physical disk writes that are necessary to maintain
the cache level, which increases system overhead and decreases performance.
When setting storage array cache settings, the value of the cacheFlushStart parameter must always be greater
than or equal to the value of the cacheFlushStop parameter. For example, if the value of the cacheFlushStart
parameter is set to 80, you may set the value of the cacheFlushStop parameter within the range of 0 to 80.
When you define values to stop a cache flush, the lower the value, the higher the chance that the data for a host read
requires a physical disk read rather than reading from the cache.
Default Host Type
When you define host types, if Storage Partitioning is enabled, the default host type affects only those virtual disks that
are mapped in the default group. If Storage Partitioning is not enabled, all of the hosts that are attached to the storage
array must run the same operating system and be compatible with the default host type.
Media Scan Rate
Media scan runs on all of the virtual disks in the storage array that have optimal status, do not have modification
operations in progress, and have the mediaScanRate parameter enabled. Use the set virtualDisk command
to enable or disable the mediaScanRate parameter.
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