Supposedly the number one reason why people experience performance issues under Linux is that they are not using Kernel hugepages and rely on AMM and /dev/shm instead.
Well, a few details about your configuration could help:
- What does /proc/meminfo on the server show?
- How is the storage connected?
- What does: "# /sbin/ifconfig -a" show?
- Are you using ASMLIB or straight ASM?
- Are you using multipath connections to storage? If so, make sure that "/etc/multipath.conf" actually identifies the composite device and not one of the physical paths.
- Are there any entries in "/var/log/messages" while running the ASM testing?
I'm sure these questions will stimulate others.