Change Cache Settings - IBM System Storage DS3500 Introduction And Implementation Manual

Draft Document for Review March 28, 2011 12:24 pm
You can select more drives in Figure 9-26 on page 246 by using the Ctrl or Shift key during
selection or by using the Select All button. All of the selected drives will have the same
modification priority after the change.

9.5.2 Change Cache Settings

Using the next option in the menu(Figure 9-25 on page 245), we change the cache settings
on the Logical Drive.
You can specify the DS3500 subsystem global cache settings, as described in "Cache
Settings" on page 205. These settings will affect all arrays and logical drives created on
the subsystem:
– Start and stop cache flushing levels
– Cache block size
You can also specify settings per logical drive:
– Read cache
– Dynamic cache read prefetch
– Write cache
– Write cache with mirroring
– Write cache without battery
Figure 9-28 shows the typical values when you create a Logical Drive with default values.
With the Storage Manager, cache settings can be specified for each logical drive
independently, giving greater flexibility.
Figure 9-28 Default values for Logical Drives
Note: We recommend that the values are manually set during creation to suit the
performance needs of the logical drive. These settings can be changed after logical drive
creation for tuning purposes.
To change this setting, highlight your logical drive in the Logical pane tree, right-click, and
select Change  Cache Settings. The window shown in Figure 9-29 on page 248 appears.
7914Admin_Logical.fm
Chapter 9. Administration - Logical Tab
247