ReadCache, WriteCache

Enter a number between 0 and 100 to specify the percentage of cache that is to be allocated to drive reads or writes. The default value for both options is 50.

The allowable cache ratios depend on the controller model and whether it has battery-backed write cache, as described in the following table.

A "+" indicates that the specified cache ratio is allowed for that type of controller, while a "" indicates that the ratio is not allowed.

Read:write ratio	RA4x00 with 16MB cache	RA4x00 with 48MB cache	All other controllers with battery-backed write cache	All other controllers without battery-backed write cache
100:0	+	+	+	+
90:10	+	+
80:20	+	+
75:25			+
70:30	+	+
60:40	+	+
50:50	+	+	+
40:60		+
30:70		+
25:75		+	+
0:50*	+
0:75*		+
0:100			+

* The cache ratio percentages do not total 100 in these cases because the additional 16-MB or 48-MB cache modules are not used. Only the battery-backed write cache is used.