topic Re: Slicing up disk in Operating System - HP-UX

Slicing up disk

MikeL_4 — Wed, 18 Apr 2007 09:53:47 GMT

We have a client that is running HPUX 11i Ver 2. They have several SAN attached 73Gb disk that are used by Oracle RAC. They want to slice the 73Gb disk up into smaller disk so the smaller units can be used as raw space in Oracle.

Is there a way to slice up a disk into smaller units ?

Re: Slicing up disk

Torsten. — Wed, 18 Apr 2007 09:58:03 GMT

Yes, but why not using LVOLs as raw space?

Re: Slicing up disk

Steven E. Protter — Wed, 18 Apr 2007 09:59:32 GMT

Shalom,

yes, levcreate

lvcreate -L 100 -n oradata vgora /dev/dsk/c1t10d0

create a 100 MB partition named oradata in volume group vgora on disk /dev/dsk/c1t10d0

That carves it up quite nicely.

SEP

Re: Slicing up disk

MikeL_4 — Wed, 18 Apr 2007 10:00:30 GMT

That's what I suggested to the client, but they are asking for a way to physically slice up a disk for there use... I think they are coming from a Solaris environment to HP..

Re: Slicing up disk

A. Clay Stephenson — Wed, 18 Apr 2007 10:02:06 GMT

Sure, that is classic LVM. Rather than using /dev/rdsk/cXtYdZ as an Oracle device, use the same disk to create an LVM volume group and then create Logical Volumes such as /dev/vg05/rlvol1, /dev/vg05/rlvol2, ... which then become your Oracle raw devices.

Re: Slicing up disk

A. Clay Stephenson — Wed, 18 Apr 2007 10:18:23 GMT

The last version of HP-UX that could create disk slices was HP-UX 9.x; later version can use the partitioned disk but not create them. Of course, disk slices have come back with IPF but the far better way to do what you are trying to do under HP-UX is LVM. If they are concerned about LVM overhead, it is all but zero. There is one extra level of kernel device switch overhead that basically reads a table to find that logical block 6512 of /dev/vg05/rlvol3 actually resides on block 512234 of /dev/dsk/c32t4d5. This indirection is all but impossible to measure and allows much more flexibility than hard disk slices.

Re: Slicing up disk

MikeL_4 — Wed, 18 Apr 2007 10:22:09 GMT

Thanks