How to get postgres to resume processes after it hangs when the RAID drive hosting the tablespace times out
You very likely have one or more failing disks, or a failing RAID controller. This would be a really good time to migrate to another host.

Also, RAID 0 across eight disks? That's asking for trouble.

In a case like this PostgreSQL will be waiting in a system call into the kernel, like a pwrite(), fsync() or similar. PostgreSQL isn't being tolerant or intolerant of your raid controller issues. It's just patiently waiting until the kernel finishes doing what PostgreSQL asks it to do and returns control to PostgreSQL. This is exactly what should happen. The problem is that the controller isn't responding so the system call never returns. You should be able to confirm this with strace or ps (though I'm not sure of the exact options on OS X).