Oracle Database Discussions

Hi,

We have installed a Oracle Database 10g R2 RAC.
The env are as follows:

OS: SELS 9 64bits
Hardware: two IBM 366 with 4CPUs
File System: OCFS2

oracle@rac1:~> ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
file size (blocks, -f) unlimited
max locked memory (kbytes, -l) 8589934590
max memory size (kbytes, -m) unlimited
open files (-n) 999999
pipe size (512 bytes, -p) 8
stack size (kbytes, -s) unlimited
cpu time (seconds, -t) unlimited
max user processes (-u) 999999999
virtual memory (kbytes, -v) unlimited

It ran quite well except a daily job.
Every night, when the job runs, we would get the errors randomly anywhere in our store procedure.
The errors are like these.

ORA-01115: IO error reading block from file 4 (block # 8713)
ORA-01110: data file 4: '/opt/oracle/oradata/dvpc/users01.dbf'
ORA-27091: unable to queue I/O
ORA-27072: File I/O error
Linux-x86_64 Error: 4: Interrupted system call
Additional information: 3
Additional information: 8699
Additional information: 49152

ORA-01115: IO error reading block from file 20 (block # 154540)
ORA-01110: data file 20: '/opt/oracle/oradata/dvpc/dvpc2nd_indx02.dbf'
ORA-27091: unable to queue I/O
ORA-27072: File I/O error
Linux-x86_64 Error: 11: Resource temporarily unavailable
Additional information: 3
Additional information: 154531
Additional information: 8192

Any suggestions would be appreciated.
Jimmy