8100 Updating Product Software Guide (XCS 6.250) (5697-1716, February 2012)

IBM AIX

Checking or changing timeouts

AIX requires the disk settings shown in Table 4 (page 27) for the native multipath drives.

Table 4 IBM AIX timeout settings

DescriptionValueSetting

Sets the key value for persistent reservations. Persistent reservations are not

supported.

NAPR_key_value

Sets the load balancing algorithm to fail_over. All I/O uses a single path;

the remaining paths are in standby mode. The value round_robin is not

supported.

fail_overAlgorithm

Sets the path health feature to check each device every 60 seconds.60hcheck_interval

Specifies the I/O paths monitored by the path health checking feature. The

value nonactive checks all I/O paths for Failed status, and checks standby

paths for Used/Opened devices.

nonactivehcheck_mode

Sets the queue depth.8queue_depth

Sets the reserve policy to standard SCSI-2 reservations.Single pathreserve_policy

Sets the read/write timeout to 60 seconds.60rw_timeout

Linux

NOTE: The RHEL 4/SLES 9 SCSI device has a default 30-second timeout value with up to 5

retries. The RHEL 5/SLES 10 SCSI device has a default 60-second timeout value with up to 5 retries.

In general, these timeout periods are sufficient for an online controller software upgrade.

Native Linux Device-Mapper Multipath

If you are using Native Linux Device-Mapper Multipath, see the Native Linux Device-Mapper

Multipath for HP StorageWorks Disk Arrays reference guide for additional configuration details.

The document is located on the Single Point of Connectivity Knowledge website:

http://www.hp.com/storage/spock

In the left navigation pane, select Solutions: Linux under Application Notes.

QLogic Driver parameters (failover enabled):

• qdepth = 16

• port_down_retry_count = 30

• login_retry_count = 30

• failover = 1

• load_balancing = 1

• excludemodel = 0x0

• auto_restore = 0xA6

QLogic Driver parameters (single path):

• qdepth = 16

• port_down_retry_count = 64

• login_retry_count = 30

• failover = 0

Managing host I/O timeouts for an online upgrade 27