Managing Serviceguard Nineteenth Edition, Reprinted June 2011

Table 5 Pros and Cons of Volume Managers with Serviceguard
TradeoffsAdvantagesProduct
• Lacks flexibility and extended features
of some other volume managers
Logical Volume
Manager (LVM)
• Software is provided with all versions of
HP-UX.
• Provides up to 3-way mirroring using optional
Mirrordisk/UX software.
• Dynamic multipathing (DMP) is active by
default as of HP-UX 11i v3.
• Supports exclusive activation as well as
read-only activation from multiple nodes
• Can be used to configure a cluster lock disk
• Supports multiple heartbeat subnets; the one
with the faster failover time is used to re-form
the cluster.
• Lacks extended features of other volume
managers
Mirrordisk/UX
• Software mirroring
• Lower cost solution
Shared Logical Volume
Manager (SLVM)
• Lacks the flexibility and extended
features of some other volume
managers.
• Provided free with SGeRAC for multi-node
access to RAC data
• Supports up to 16 nodes in shared read/write
mode for each cluster • Limited mirroring support
• Supports exclusive activation
• Supports multiple heartbeat subnets.
• Online node configuration with activated
shared volume groups (using specific SLVM
kernel and Serviceguard revisions)
Base-VxVM
• Cannot be used for a cluster lock• Software is supplied free with HP-UX 11i
releases.
• Supports only exclusive read or write
activation
• Java-based administration through graphical
user interface.
• Package delays are possible, due to
lengthy vxdg import at the time the
package is started or failed over
• Striping (RAID 0) support.
• Concatenation.
• Online resizing of volumes.
• Supports multiple heartbeat subnets.
Veritas Volume
Manager— Full VxVM
product
• Requires purchase of additional license• Disk group configuration from any node.
• •DMP for active/active storage devices. Cannot be used for a cluster lock
•• Does not support activation on multiple
nodes in either shared mode or
read-only mode
Supports exclusive activation.
• Hot relocation and unrelocation of failed
subdisks
• May cause delay at package startup
time due to lengthy vxdg import
• Supports up to 32 plexes per volume
• RAID 1+0 mirrored stripes
• RAID 1 mirroring
• RAID 5
• RAID 0+1 striped mirrors
• Supports multiple heartbeat subnets, which
could reduce cluster reformation time.
Veritas Cluster Volume
Manager
• Disk groups must be configured on a
master node
• Provides volume configuration propagation.
• Supports cluster shareable disk groups.
• Cluster startup may be slower than with
VxVM
• Package startup time is faster than with VxVM.
84 Understanding Serviceguard Software Components