Oracle Grid Infrastructure Installation Guide 11g Release 2 (11.2) for Linux Part Number E22489-05
2.6.2 Server Hardware Requirements
6.5 GB of space for the Oracle Grid Infrastructure for a Cluster home (Grid home) This includes Oracle Clusterware and Oracle ASM files and log files, ACFS log files, and includes the Cluster Health Monitor repository, if available for your platform.
http://docs.oracle.com/cd/E11882_01/install.112/e22489/prelinux.htm#autoId25
