Heartbeat restriction

[Bruno Bossier_1]

The Serviceguard documentation says the following on heartbeat's :

"HEARTBEAT_IP

IP notation indicating the subnet that will carry the cluster heartbeat. Note that heartbeat IP addresses must be on the same subnet on each node. A heartbeat IP address can only be an IPv4 address.

If you will be using VERITAS CVM disk groups for storage, you can only use a single heartbeat subnet. In this case, the heartbeat should be configured with standby LANs or as a group of aggregated ports. "

We are using CVM thus have this restriction. However, how do I have to interprete this restriction. Does this mean that I can only configure 1 interface as heartbeat interface or can I configure multiple interfaces as heartbeat as long as the ip addresses configured for those interfaces all belong to the same network subnet ?

Any ideas ?

Bruno

[John Poff]

Hi Bruno,

Where did you see the restriction about Veritas CVM? I'm not famililar with that, but I've never heard of heartbeat restrictins like that before.

JP

[Slawomir Gora]

Hi,

I think you can use only one network interface
per host for heartbeat.

from manual:

This restriction is due to the design of the VERITAS Cluster Daemon (vxclustd), which is started within the VxVM-CVM-pkg. This daemon is only able to communicate information to cluster nodes on a single IP connection on a single subnet.

[Steve Steel]

Hi


From the release notes

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B3935-90063/B3935-90063_top.html&con=/hpux/onlinedocs/B3935-90063/00/00/6-con.html&toc=/hpux/onlinedocs/B3935-90063/00/00/6-toc.html&searchterms=cvm&queryid=20041022-062229

Restrictions and Limitations with VxVM and CVM Storage
Some restrictions and limitations of VxVM and CVM storage support should be noted:

VxVM disks cannot be used as cluster lock disks.

In clusters that will use CVM storage, only a single heartbeat subnet may be used, which CVM also uses for its own communication among cluster nodes.

At first release, CVM disk groups and VxVM disk groups cannot be used within the same cluster. However, you can use VxVM private disk groups on CVM cluster nodes without problems as long as they are not imported by a package running in the cluster.

VxVM and CVM support are fully documented in the manual Managing MC/ServiceGuard.


The manual is available at www.docs.hp.com
http://www.docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B3936-90073/B3936-90073_top.html&con=/hpux/onlinedocs/B3936-90073/00/00/39-con.html&toc=/hpux/onlinedocs/B3936-90073/00/00/39-toc.html&searchterms=cvm&queryid=20041022-061137


This all means that the heartbeat lans should be on the same subnet .

http://docs.hp.com/hpux/ha/



Steve Steel

[Steven E. Protter]

I have to agree with the last post.

Heartbeat between two lan cards won't work if they are not on the same subnet.

It is possible to have more than one heartbeat set up and may even be a good idea with SG.

SEP

[Stephen Doud]

Bruno,

Page 63 of http://docs.hp.com/hpux/pdf/B3936-90079.pdf states this:

IMPORTANT
Multiple heartbeats are sent in parallel. It is normally recommended
that you configure all subnets that interconnect cluster nodes as
heartbeat networks, since this increases protection against multiple
faults at no additional cost. However, if you will be using the VERITAS
Cluster Volume Manager (CVM), you can use only a single heartbeat
subnet. In this case, the heartbeat should be configured with standby
LANs or as a group of aggregated ports. See below, â Single Heartbeat
Subnet Required with CVM.â


I do not believe the subnet reference above is clearance to use multiple HB LANs other than in an APA configuration.

[Bruno Bossier_1]

OK, from what I understand from all the replies (thanks for that !) it should be possible to use several interfaces as heartbeat as long as they are all configured withing the same subnet. I take my example :

The 2 nodes in my cluster have each connections to 2 seperate subnets with a standby NIC for each connection, so 4 NIC's in total. I configured one of the 2 subnets as HEARTBEAT_IP and the other one as STATIONARY_IP.

I should now be able to configure a 5th NIC on each node who will be connected point-to-point with each other and with an ip address in the same subnet as used for the HEARTBEAT_IP ?

Correct ?

Bruno