Cluster Configuration

[simon_164]

I am preparing a testing environment to prepare an installation I have some questions:

1- Can I build a cluster with 2 nodes without a shared storage,
I know it's not supported by Hp but could it be done?

2- Is it better to create the cluster lock disk alone? because i can present a disk from EVA and make it the cluster lock disk. Is it better to be alone or within the package?

[Prashanth.D.S · Accepted solution]

Hi Simon,

Yes you are right u cannot build any cluster without a shared storage...

2. Its better to create a cluster lock disk alone, if you are using a EVA you can present a lun for the same. Its not recommended to keep cluster lock and package in a same disk.


Best Regards,
Prashanth

[Mridul Shrivastava]

The cluster lock disk (used only in HP-UX clusters) is a disk that can be written to by all members of the cluster. When a node obtains the cluster lock, this disk is marked so that other nodes will recognize the lock as "taken." This mark will survive an off-on power cycle of the disk device unlike SCSI disk reservations. A lock disk may be used for clusters of up to four nodes.

The lock is created in a special area on a particular LVM physical volume. The cluster lock volume group and physical volume names are identified in the cluster configuration file.

The lock disk is not dedicated for use as the cluster lock; thus, it can be employed as part of a normal volume group with user data on it. The usable space on the disk is not impacted; the lock disk takes no space away from the disk's volume group. Further, the activation of the volume group on one node does not affect the ability of another node to acquire the cluster lock.

The lock area on the disk is not mirrored, even though the physical volume may be a part of a volume group that contains mirrored logical volumes.

For more information please have a look of the following link:
http://docs.hp.com/en/B3936-90078/ch01s04.html

[Kenan Erdey]

hi;

storage may not be shared. you may want a active-passive cluster type. When volume groups are activated in exclusive mode in one node, they are not activated in the other one. if active node fails, package is activeted on the other.

no need to make cluster disk alone i think.

[Michael Steele_2]

2) cluster lock disk
The cluster lock disk (used as a tie-breaker when re-forming a cluster) should have a redundant power supply, or else it
can be powered from a different supply than the nodes in the cluster. The lock disk is known as a tie breaker and used to prevent 'split brain' cluster. Where both nodes come up active and grab the cluster. With a lock disk, the first node up to the lock disk wins. In lieu of a lock disk you can also use a quorum server, which is a third server outside of the cluster. Often in another building. And of course you don't need the cluster lock, lock disk or quorum server in a one node cluster.

1) Not using shared storage in service guard. Well, vg00 and vg01, (* where the HP-UX O/S resides *), are not shared and reside in local disks to node1 and node 2. (vg00 on node1 and vg01 on node2 ) So yes, you can put your file system into local disks, specific only to each node, just like vg00 and vg01. In fact, I've done this but the application and file systems on this disks will never fail over. In short, you've essentially got a stand alone file system running on one node in a service guard cluster. My reason for doing this was a utilization reason. I had 4 36 GB disks on one node and that was way too much disk for vg00, which only need 2 of the 4 36 GB disks. so I used the other two 36 gb disks for a name server, else they would would have gone to waste.