• From: "Kevin Closson" <kevinc@xxxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Thu, 28 Dec 2006 10:19:31 -0800

Naqi sent me the HP doc. It says that ASM->SLVM is for multi-pathing,
device naming and external-write protection... three of the reasons
deploy RAC on PolyServe in the Linux world btw...

I have seen that Oracle is starting to admit this necessity in other
technology stacks as well such as VxVM with Sol or AIX.

 The main reason for this requirement is to expedite ASM support with
SGeRAC. We leverage existing
HP-UX capabilities to provide multipathing for SLVM logical volumes,
using either the PV Links feature,
or separate products such as HP StorageWorks Secure Path that provide
multipathing for specific
types of disk arrays. Other advantages of the "ASM-over-SLVM"
configuration are as follows:
* ASM-over-SLVM ensures that the HP-UX devices used for disk group
members will have the
same names (the names of logical volumes in SLVM volume groups) on all
nodes, easing
ASM configuration.
* ASM-over-SLVM protects ASM data against inadvertent overwrites from
nodes inside/outside
the cluster. If the ASM disk group members are raw disks, there is no
protection currently
preventing these disks from being incorporated into LVM or VxVM
volume/disk groups.

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