The following are two tests I ran inside a VM. One is to the OS drive which is inside a regular VMFS datastore, the other is to a mapped raw lun. Both are on the same backend storage (Equallogic iSCSI) connected via fixed MPIO 1 Gb/s. Should I be seeing that kind of difference and is 37 MB/s OK?
# dd if=/dev/zero bs=9000 count=100000 of=test && rm -f test
100000+0 records in
100000+0 records out
900000000 bytes (900 MB) copied, 8.83205 seconds, 102 MB/s
# dd if=/dev/zero bs=9000 count=100000 of=test && rm -f test
100000+0 records in
100000+0 records out
900000000 bytes (900 MB) copied, 23.9424 seconds, 37.6 MB/s
