Clustering Linux Servers with the Concurrent Deployment of HP Serviceguard Linux and Red Hat Global File System for RHEL5, October 2008

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finally changing the super block of each GFS file system to use the DLM locking protocol
using the gfs_tool.
2. Upgrade your operating system to Red Hat Enterprise Linux 5.
Then Serviceguard cluster and packages are started up on RHEL5 systems with DLM lock
manager.
For information on upgrading to Red Hat Enterprise Linux 5 and converting GFS file systems to use
the DLM lock manager, see “Configuring and Managing a Red Hat Cluster for RHEL5” document
available at: http://www.redhat.com/docs/manuals/csgfs/
.
Package configuration
This section discusses about the guidelines to be followed when configuring a package in
Serviceguard for Linux with Red Hat GFS for RHEL5.
In a Serviceguard cluster without a clustered file system, at package startup, the file system
consistency checks (i.e., fsck) are done and logical volumes are mounted. But when supporting
Serviceguard with Red Hat GFS the package is started without the fsck (file system check) and
mounting of the file system. So an administrator of a dual Serviceguard and Red Hat GFS cluster
needs to take care that a GFS mount point needed by a package is already mounted. HP
recommends that all Red Hat GFS partitions are mounted on a Red Hat GFS node during system
initialization as suggested by the Red Hat GFS Administration manual. This is done by adding
appropriate entries in the /etc/fstab file and enabling Red Hat cluster services to start at machine
startup time. The device name entries needed in the /etc/fstab file for Red Hat GFS for RHEL5
follows the device name formats of LVM2 volume managers.
However if the file system is not already being mounted, the package startup script mounts them;
fsck operations are not performed. This is achieved by specifying the Red Hat GFS partitions
required by the application in its package configuration file.
Since the GFS mount points remain mounted always on all nodes in the cluster, the LVM2 volume
groups must not be deactivated on any of the nodes in the cluster. Hence during package
shutdown the GFS file system is not un-mounted.
Modular Package configuration
After creating a modular package configuration the guidelines described below needs to be
followed.
LV designators are used to specify the LVM2 volumes in case of Red Hat GFS for RHEL5 (similar to
what is used for Red Hat GFS 6.1). LVM2 device names are of the format /dev/mapper/vgX-lvY
where vgX is the volume group and lvY is the logical volume. Set the variable fs_type, to “gfs” to
indicate Red Hat GFS file system. Set the parameters, fs_name, file_directory, and fs_mount_opt
which are used to check whether the files system is already mounted, and if required, mounts
them. The parameters, fs_umount_opt and fs_fsck_opt are incompatible. These variables will not
be used at the time of package startup or shutdown. Also the variable fs_mount_retry_count is
assumed to be “0”.
Since the GFS file system is not un-mounted during package shutdown, the vgchange_cmd and
VG variables are ignored.