HP manual Pros and Cons of Volume Managers with Serviceguard

Table 5 Pros and Cons of Volume Managers with Serviceguard

Product

Advantages Tradeoffs

Logical Volume Manager (LVM)

Mirrordisk/UX

•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.

•Software mirroring

•Lower cost solution

•Lacks flexibility and extended features of some other volume managers

•Lacks extended features of other volume managers

Shared Logical Volume Manager (SLVM)

Base-VxVM

•Provided free with SGeRAC for multi-node access to RAC data

•Supports up to 16 nodes in shared read/write mode for each cluster

•Supports exclusive activation

•Supports multiple heartbeat subnets.

•Online node configuration with activated shared volume groups (using specific SLVM kernel and Serviceguard revisions)

•Software is supplied free with HP-UX 11i releases.

•Java-based administration through graphical user interface.

•Striping (RAID 0) support.

•Concatenation.

•Online resizing of volumes.

•Supports multiple heartbeat subnets.

•Lacks the flexibility and extended features of some other volume managers.

•Limited mirroring support

•Cannot be used for a cluster lock

•Supports only exclusive read or write activation

•Package delays are possible, due to lengthy vxdg import at the time the package is started or failed over

Veritas Volume Manager— Full VxVM product

•Disk group configuration from any node.

•DMP for active/active storage devices.

•Supports exclusive activation.

•Hot relocation and unrelocation of failed subdisks

•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.

•Requires purchase of additional license

•Cannot be used for a cluster lock

•Does not support activation on multiple nodes in either shared mode or read-only mode

•May cause delay at package startup time due to lengthy vxdg import

Veritas Cluster Volume • Provides volume configuration propagation.
Manager	• Supports cluster shareable disk groups.
	• Package startup time is faster than with VxVM.

•Disk groups must be configured on a master node

•Cluster startup may be slower than with VxVM

Volume Managers for Data Storage 87