HP/UX to Linux - raw space setup question

We are moving from 9.4 on HP/UX 11.11 (physical/hard drives) to 11.1 on RHEL 5 (VMWare/SAN) and have a couple of questions about the raw storage setup. In HP/UX, the Unix system administrator (no longer here) put the hard drives in a volume group. From that volume group, I would use SAM to create raw logical volumes that created both character and block devices. I then used symbolic links to the character devices and used those as my chunks for the dbspaces. For RHEL, the Linux system administrator (not familiar with raw devices) has been given a chunk of SAN space and we are not sure how to get it from there to the character devices I need to setup up my symbolic links. The SAN space can be seen in /dev as a block device already, but my reading leads me to believe I need to use raw to do something next. Also, everything for RHEL seems to point to using block devices and not the character devices we currently use, so not sure what I should do next. Anyone with RHEL using raw space that could provide a quick step by step process to follow would be appreciated. We don't mind having to research how to do those steps or use the necessary tools, just not sure what the steps are to create and size the raw devices. HP/UX setup (subset of all devices/links for illustration): Devices created by using SAM to create logical volumes within the volume group: brw-rw-rw- 1 informix informix 64, 65559 Jun 30 2006 1gbdbs1 brw-rw-rw- 1 informix informix 64, 65560 Jun 30 2006 1gbdbs2 brw-rw-rw- 1 informix informix 64, 65562 Oct 30 2007 1gbdbs3 brw-rw-rw- 1 informix informix 64, 65563 Apr 16 2008 2gbdbs crw-rw-rw- 1 informix informix 64, 65559 Jun 30 2006 r1gbdbs1 crw-rw-rw- 1 informix informix 64, 65560 Jun 30 2006 r1gbdbs2 crw-rw-rw- 1 informix informix 64, 65562 Oct 30 2007 r1gbdbs3 crw-rw-rw- 1 informix informix 64, 65563 Apr 16 2008 r2gbdbs Symbolic links created to use as the chunks for the dbspaces: lrwxrwxrwx 1 informix informix 18 Jun 30 2006 1gbdbs1 -> /dev/vg01/r1gbdbs1 lrwxrwxrwx 1 informix informix 18 Jun 30 2006 1gbdbs2 -> /dev/vg01/r1gbdbs2 lrwxrwxrwx 1 informix informix 18 Oct 30 2007 1gbdbs3 -> /dev/vg01/r1gbdbs3 lrwxrwxrwx 1 informix informix 17 Apr 16 2008 2gbdbs -> /dev/vg01/r2gbdbs Linux info: /dev folder brw-r----- 1 root disk 8, 0 Oct 26 07:59 sda (big SAN chunk) brw-r----- 1 root disk 8, 1 Oct 26 07:59 sda1 (partitioned sda space for file system) brw-r----- 1 root disk 8, 2 Oct 26 07:59 sda2 (partitioned sda space for file system) brw-r----- 1 root disk 8, 3 Oct 26 07:59 sda3 (partitioned sda space for swap file) parted info Model: VMware Virtual disk (scsi) (from the SAN) Disk /dev/sda: 69.8GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 9434MB 9434MB primary ext3 boot 2 9434MB 14.7GB 5240MB primary ext3 3 14.7GB 16.8GB 2097MB primary linux-swap TIA, Randy

Hi Randy. IDS 11 supports IO_DIRECT, meaning it will use a block device as efficiently as a character device, which is fortunate as the latter is deprecated. Make sure KAIO is being used. There is a pseudo character device in Linux which you can bind to the block device, but our findings are that there is no benefit and it's actually slower on some hardware. If you have a large device presented by the SAN, either break it into logical volumes or create multiple chunks at offsets within it. Don't use huge chunks or it will slow down checkpoints. Usual advice regarding functional separation of dbspaces apply. Continue to use symbolic links to the devices. Regards, Doug Lawry