Uhh...Informix on block device?!

Dear Gurus, I'm just taking up a sysadm/DBA on a new job. Just found that our Informix is using raw chunks but these chunks point to the block device under /dev. (e.g., /dev/lv00 as opposed to /dev/rlv00). This is _extremely_ weird to me, as I know we should use /dev/rlv00, but Informix is still happy about it. I'm concerned about the /dev/lv00 is buffered I/O device and something worst could happen. On the other hand, a simple "dd" tests shows (not surprisingly) the block device are faster than raw devices...so... Any input to help me to talk out with management... Thanks. Chris