VERITAS Storage Foundation 4.1 Oracle Administrator's Guide

VERITAS Volume Manager Prerelease 8 September 2005, 8:54am
32 VERITAS Storage Foundation for Oracle Administrator’s Guide
VxVM detects I/O failures on volumes and relocates the affected portions to disks designated as
spare disks or free space within the disk group. VxVM then reconstructs the volumes that existed
before the failure and makes them redundant and accessible again.
The hot-relocation feature is enabled by default and is recommended for most database
configurations. After hot-relocation occurs, we recommend verifying the volume configuration for
any possible performance impact. It is also a good idea to designate additional disks as spares to
augment the spare pool.
While a disk is designated as a spare, you cannot use the space on that disk for the creation of
VxVM objects within its disk group. VxVM also lets you free a spare disk for general use by
removing it from the pool of hot-relocation disks.
DMP-Supported Disk Arrays
VxVM provides administrative utilities and driver support for disk arrays that can take advantage
of its Dynamic Multipathing (DMP) feature. Some disk arrays provide multiple ports to access their
disk devices. These ports, coupled with the host bus adaptor (HBA) controller and any data bus or
I/O processor local to the array, make up multiple hardware paths to access the disk devices. Such
disk arrays are called multipathed disk arrays. This type of disk array can be connected to host
systems in many different configurations, (such as multiple ports connected to different controllers
on a single host, chaining of the ports through a single controller on a host, or ports connected to
different hosts simultaneously). DMP is available for multiported disk arrays from various vendors
and provides improved reliability and performance by using path failover and load balancing.
See the VERITAS Volume Manager Administrator’s Guide for detailed information and the
VERITAS Volume Manager Hardware Notes for information about supported disk arrays.
Dynamic LUN Expansion
Dynamic LUN expansion allows you to resize a disk after it has been initialized while preserving
the existing data on the disk. See the VERITAS Volume Manager Administrator’s Guide for more
information.
Storage Expert
Storage Expert consists of a set of simple commands that collect VxVM configuration data and
compare it with “best practice.” Storage Expert then produces a summary report that shows which
objects do not meet these criteria and makes recommendations for VxVM configuration
improvements.
These user-configurable tools help you as an administrator to verify and validate systems and
non-optimal configurations in both small and large VxVM installations.