RE: using LVM PV links with Informix on HP-UX

I would recommend that you create volume groups over the physical volumes that way you can access the volume group through alternative paths without affecting the configuration of your RDBMS On the volume group create logical volumes and use the raw version to link with soft links to your chunk See this example: VG Name /dev/vgGM4 VG Write Access read/write VG Status available Max LV 255 Cur LV 7 Open LV 7 Max PV 16 Cur PV 1 Act PV 1 Max PE per PV 2102 VGDA 2 PE Size (Mbytes) 4 Total PE 2102 Alloc PE 1792 Free PE 310 Total PVG 0 --- Logical volumes --- LV Name /dev/vgGM4/lvol1 LV Status available/syncd LV Size (Mbytes) 1024 Current LE 256 Allocated PE 256 Used PV 1 LV Name /dev/vgGM4/lvol2 LV Status available/syncd LV Size (Mbytes) 1024 Current LE 256 Allocated PE 256 Used PV 1 ....... ....... --- Physical volumes --- PV Name /dev/dsk/c4t1d4 PV Name /dev/dsk/c3t0d4 Alternate Link PV Status available Total PE 2102 Free PE 310 Here I have created a volume group vgGM4 over a LUN that is accessed though two alternative paths c4t1d4 and c3t0d4 Then I created the logical volumes lvol1, lvol2 .... and of course I have the corresponding raw volumes rlvol1, ... in /dev/vgGM4/rlvol1 .... After that create a directory where you feel a good place in my case /dev/informix/XX and make soft links to this directory e.g. ln -s /dev/vgGM4/rlvol1 /dev/informix/XX/mychunk1 remember to put the volumes with the correct permission informix:informix 660 yours > N. Daniel Bonesana > SIEMENS-ITRON BUSINESS SERVICES S.A. > Balcarce 683, (C1064AAM) Buenos Aires, Argentina. > * 54 (11) 4320-5456 * Daniel.Bonesana@siemens-itron.com.ar > > -----Original Message----- From: yixes@my-deja.com [mailto:yixes@my-deja.com] Sent: Monday, October 30, 2000 4:20 PM To: informix-list@iiug.org Subject: using LVM PV links with Informix on HP-UX on our HP K460 i am using LVM to manage the LUN that our Informix implementation has all its raw space located. there are 4 device file paths to this LUN, 2 becuase there are 2 host bus adapters, and 2 becuase there are two RAID controllers. i will call these paths A,B,C, and D. PROBLEM: currently we are only using A, but for failover i added B as a PV link. Informix did not complain after the reboot. BUT when i decided to make B the primary path and A the alternate path, then Informix would not initialize after reboot. It could not find the last checkpoint in the root dbspace. QUESTION: does Informix support PV links? that is, if the primary path A to the LUN fails becuase of a hardware failure of a host bus adapter, then will Informix be "happy" when LVM sends I/O thru the failover path B??? NOTE: Informix was built using the LV device file names not the LUN device file names. I am assuming that using LV device file names are like using soft links to actual LUN device file names, because of LVM's ability to manage disks within a VG Sent via Deja.com http://www.deja.com/ Before you buy.