I am going to install Oracle RAC on two Servers, With shared SAN storage (Servers and Storage is IBM)
OS = RHEL 5u5 x64 bit
And we used multipathing mechanism and created multipathing devices.
Then I created raw device /dev/raw/raw1 of this /dev/mapper/mpath1 Block device as per pre-reqs for Oracle Cluster.
Every thing looks good, But we faced the performance issue as under...
when we run command :
#dd if=/dev/zero of=/dev/mapper/mpath1 bs=1024 count=1000
the writing rate is approx. 34 MB/s
If we run command
#dd if=/dev/zero of=/dev/raw/raw1 bs=1024 count=1000
the writing rate is very slow like 253 KB/s
Please advice how to tune the performance.