Release Notes Device Mapper Multipath Enablement Kit for HP StorageWorks Disk Arrays v4.1.0 (AA-RWF9E-TE, November 2008)

Over view
HPDM Multipath software kit is a HP released multipath enablement kit for HP Stora geWorks Disk
Arrays, base
d on Device M apper M ultipath included in Linux operating system distributions. This release
notes discus
ses the recent product informa tion about HP Device Mapper Multipath (HPDM M u ltipath)
Enablement Kit for HP StorageWorks Disk Arrays v4.1.0.
Device Mapper Multipath offers the following features:
• I/O failover and failback: Provides transparent failover and failback of I/Os by rerouting I/Os
automatically to an alternative path when a path failure is sensed and routing them back when
the path is
restored.
• Path grouping policies: Paths are coalesced based on the following path-grouping policies:
1. Priority based path-grouping
•Providesp
riority to group paths based on Asymmetric Logical Unit Access (ALUA) state
• Provides static load balancing policy by assigning higher priority to the preferred path
2. Multibus
• All paths
are grouped under a single path group
3. Group by serial
• Paths are groupe d together based on controller serial number
4. Failove
ronly
• Provides failover without load balancing by grouping the paths into individual path groups
• I/O load balancing policies: Provides weighted Round Robin load balancing policy within
a path g
roup.
• Device name persistence: Device names are persistent across reboots and Storage Area N etwork
(SAN) reconfigurations. Device Map per also provides configurabledevicenamealiasingfeature
for easier management.
• Persistent device settings: All the device settings such as load balancing policies, path grouping
policies are persistent across reboots and SAN reconfigurations.
• Devi
ce exclusion: Provides device exclusion feature through blacklisting of devices.
• Path monitoring: Periodically monitors each pa th for status and enables faster failover and
failback.
• Online device addition and deletion: Devices can be added to or d eleted from Device Mapper
(DM
) multipath without rebooting the server or disrupting other devices or applications.
• Management Utility: Provides Command Line Interface (CLI) to mana ge multipath devices.
• Boot from SAN: Provides multipathing for operating system installation partitions on SAN device.
NOT
E:
Mul
tipathing for SAN Boot environm ent is supported on the following operating systems: RHEL 5 U1/RHEL
5U
2/SLES 10 SP1/SLES 10 SP2. For more details on multipathing support for SAN Boot e nvironment,
se
ethe
Booting Linux x86 and x86_64 systems from a Storage Area Network with Device Mapper
Mu
ltipath
document available at http://h18006.www1.hp.com/storage/networking/bootsan.html.
What’s new
HPDM Multipath v4.1.0 provides the following additional features:
• Provides utilities and device parameter values to enable multipathing for H P BladeSystem external
SAS Storage (MSA2012sa) Disk Arrays.
• Provides multipath support for Xen enabled vir tual machines on RHEL 5 U2 operating system.
• Provides multipath support with data replication solutions, Business Copy a nd Continuous Access
for HP Storag eWorks E nterprise Virtual Arrays and XP D isk Arrays.
Device Mapper Multipath Enablement Kit for HP StorageWorks Disk Arrays v4.1.0
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