Silicon Graphics InfiniteStorage 4000 Series, Configuring And Maintaining

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74 Modifying Your Configuration
For example, if you set the
defaultHostType
parameter to
Linux
, the controller
communicates with any undefined host if the undefined host is running a Linux
operating system. Typically, you would need to change the host type only when you
are setting up the storage array. The only time that you might need to use this
parameter is when you need to change how the storage array behaves relative to the
hosts that are connected to it.
Before you can define the default host type, you need to determine what host types are
connected to the storage array. To return information about host types that are
connected to the storage array, use the
show storageArray
command with the
defaultHostType
parameter or the
hostTypeTable
parameter. This
command returns a list of the host types with which the controllers can communicate.
This command does not return a list of the hosts. These examples show the use of the
show storageArray
command:
c:\...\sm X \client>smcli 123.45.67.88 123.45.67.89

-c “show storageArray defaultHostType;”
c:\...\sm X \client>smcli 123.45.67.88 123.45.67.89

-c “show storageArray hostTypeTable;”
This example shows how to define a specific default host type:
c:\...\sm X \client>smcli 123.45.67.88 123.45.67.89

-c “set storageArray defaultHostType=11;”
The value
11
is the host type index value from the host type table that appears after
entering the previous command.
Setting the Storage
Array Cache
The cache is high-speed memory that holds data that is either written to the drives or
read by the host. A controller has two memory areas that are used for intermediate
storage of read data and write data. The read cache contains data that has been read
from the drives but not yet transferred to the host. The write cache contains data from
the host but not yet written to the drives.
The cache acts as a buffer so that data transfers between the host and the drive do not
need to be synchronized. In read caching, the data for a read operation from the host
might already be in the cache from a previous operation, which eliminates the need to
access the drives. The data stays in the read cache until it is flushed. For write
caching, a write operation stores data from the host in cache until it can be written to
the drives.
The script command set provides two commands to define cache properties:
 set storageArray
 set volume
Use the
set storageArray
command to change the cache block size, the cache
flush start value, and the cache stop value. The command has this form: