Linux management of volume groups

[Enrico Venturi]

Hello collegues,
we currently run some applications in HP-UX 11i environment.
We're migrating the SW platform to Linux Red Hat.

In HP-UX we use the Logical Volume file system, and through the system call vgdisplay, vgchange and vgsync we've setup a shared disks manager, something similar to MC-ServiceGuard in that we're able to synchronize the several nodes of the cluster during the access to the shared resources (e.g. disks and IP addresses).

In Linux I need some system calls to manage the volume groups and I'd like to know if there are primitives to lock / unlock the shared disks when mounted by a node of the cluster.
I'd like to know if Linux has embedded some utility to syncronize the nodes when accessing a shared disks.

Sorry if my question is too much generic or stupid at all ;-)

thanks
Enrico

[Serviceguard for Linux]

First - I assume you are using RedHat 4.

RedHat 4 uses LVM2. It does not have exclusive activation built in. There is a Clustered Logical Volume Manager (CLVM) that is designed to work with Clustered File Systems and only works (to my knowledge) with RedHat's clustered file system - GFS. I think the CLVM APIs are available.

Which cluster are you planning to use? If it is Serviceguard for Linux, we are releasing a feature in our new release (due out by the end of October) that works around the lack of this LVM function and provides exclusive activation within the cluster.

If you are planning on using Serviceguard for Linux have your sales person contact the lab to get more detailed information.

Many other Linux clusters do not support LVM in the cluster. The open source clusters use "STONITH" for data protection. WIth STONITH a node uses various mthods to reset another node that it has determined has "failed".