IBM System Storage DS3000, Руководство по программированию

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parameter defines the host type only for data I/O activities of the storage subsystem. This parameter
does not define the host type for the management station. The operating system can be Windows, Linux,
or Solaris.
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 subsystem. The only time that you might
need to use this parameter is if you need to change how the storage subsystem 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 subsystem. To return information about host types that are connected to the storage subsystem,
use the
show storageSubsystem
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
storageSubsystem
command:
c:\...\...\client>smcli 123.45.67.89 -c “show storageSubsystem defaultHostType;”
c:\...\...\client>smcli 123.45.67.89 -c “show storageSubsystem hostTypeTable;”
This example shows how to define a specific default host type after displaying the host type table:
c:\...\...\client>smcli 123.45.67.89 -c “set storageSubsystem defaultHostType= xx ;”
where xx is the host type index value. For value xx , refer to the previously-displayed host type table.
From the table, select the appropriate value for the host server that the LUN from the storage subsystem
is mapped to.
Setting the Storage Subsystem Cache
The cache is high-speed memory that holds data that is either written to the disk drives or read by the
host. A controller has two memory areas used for intermediate storage of read data and write data. The
read cache contains data that has been read from the disk drives but not yet transferred to the host. The
write cache contains data from the host but not yet written to the disk drives.
The cache acts as a buffer so that data transfers between the host and the disk 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 disk 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 disk drives.
Important: Changing default cache settings is not recommended – IBM recommends that you do not
change the default cache setting values. Incorrect cache settings might severely affect the storage
subsystem performance.
The script command set provides two commands to define cache properties:
v set storageSubsystem
v set logicalDrive
Use the
set storageSubsystem
command to change the cache block size, the cache flush start value, and
the cache stop value. The command takes this form:
set storageSubsystem cacheBlockSize= cacheBlockSizeValue |
cacheFlushStart= cacheFlushStartSize |
cacheFlushStop= cacheFlushStopSize
You can enter one, two, or all three of the parameters on the command line.
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IBM System Storage DS3000, DS4000, and DS5000: Command Line Interface and Script Commands Programming Guide