Re: multipath slvm hp-ux 11.23 - asm or raw??

From: Svetoslav Gyurov <>
Date: Fri, 01 Feb 2008 11:20:57 +0200
Message-ID: <>

Hi Ujang,

 From Oracle 10g and appearing of Cluster Ready Services it is not necessary to use SLVM, you can use disks device files as well, BUT first there is no guarantee that the names of the devices files will be the same at all nodes and second if someone decide to execute pvcreate at some of these files there is no warning message and all your data will be gone.

About your questions:
1. If you want to use SLVM you need to use Service Guard and Service Guard Extension for RAC.
2. LVM natively have alternate links which offers you failover and not load balancing if this is what you called multipath. Better way to have real multipath (load balancing and failover) is to use Secure Path depending of the mode of the storage (Active-Passive or Active-Active) and this is for HP-UX 11iv2 (HP-UX 11iv3 does have native multipath for AA mode).
3. Yes, I think it is good idea. Depends if you use SLVM then your can use ASM over SLVM raw device and yes you have at least better management. 4. Yes, it used to be impossible, but before two years HP released Service Guard Extension for RAC 11.17 which offered new functionality called SNOR (Single Node Online Reconfiguration), it is also available as a patch. Actually this new feature gives you the ability to shutdown all the nodes in the cluster but one and then on this particular node you can change the mode of the volume group without deactivating it, make the appropriate changes, propagate the change to the other nodes, move the volume group back to shared mode and then activate it at all other nodes. For more information please read: 5. In the concepts of HP-UX this is called APA (auto port aggregation), bonding is on Linux and timing is on Windows. Actually Service Guard cannot aggregate ports, but can failover NICs by configuring and using standby network interfaces i.e. your Service Guard is using lan0 for HEARTBEAT and lan1 is standby network for interface lan0. So in case of failure of lan0, Service Guard will automatically bring lan1 online and try to resume the connection to the other node(s) through this interface.

My personal opinion is to use SLVM over SGeRAC for several reasons: 1. Control - SG is flexible and offers better control. By using raw device files once the machine boots the Cluster Ready Services are started immediately and you have less control. 2. Identical logical volume names on all nodes on the cluster and naming convention
3. Some kind of protection - accidentally doing pvcreate will be refuser because the device is already initialized 4. Last but not at least Service Guard support for the SGeRAC Toolkit giving you integration between SGeRAC and Oracle10g stack. Better control by using multinode packages, package dependencies, cluster interconnect subnet monitoring and several other good features.

Hope it helps.


Ujang Jaenudin wrote:

> all,
> I have itanium machine and hp-ux 11.23 installed, with 2 hba for each machine.
> I plan to use Shared LVM - raw.
> - I plan to not use serviceguard
> - is shared LVM natively support multipath (i means there is no
> multipath software from storage)
> - is it good idea to use ASM on top of shared LVM raw device?? - i
> thinking of easy management...
> i heard on shared LVM could not doing online changes.....
> - is NIC bonding/teaming can be configured without serviceguard??
> thanks for the sharing....
Received on Fri Feb 01 2008 - 03:20:57 CST

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