VERITAS Storage Foundation 4.1 Release Notes

New and Enhanced Features
8 VERITAS Storage Foundation Release Notes
◆ DMP supports the B_FAILFAST flag if the underlying device driver exports the
ddi-failfast-supported property. The B_FAILFAST flag allows the disk drivers to
avoid heroic, time-consuming retry behavior when it is not required or is inappropriate. The
B_FAILFAST flag is intended to allow modified error recovery behavior in the disk driver
when no communication can be established with the device. However it does not dictate
specific retry behavior, nor does it imply or guarantee deterministic failure times.
When I/O is requested to a device associated with the ddi-failfast-supported
property, and the device has multiple paths available or I/O request is for a Read operation
from a volume that has an alternate source (mirror), DMP will set the B_FAILFAST flag in the
I/O request. While DMP sets the B_FAILFAST flag, DMP has no knowledge of whether the
underlying disk driver’s behavior is influenced by B_FAILFAST.
◆ Performance improvements have been made to DMP.
Device Discovery Layer Enhancements
The Device Discovery Layer (DDL) was introduced in an earlier release of VxVM. This release
enhances the DDL by adding the following functionality:
◆ DDL services are now available to other VERITAS products through VERITAS Enterprise
Administrator (VEA).
◆ Dynamic discovery of disks or their attributes
◆ Allowing DMP kernel extensions to support multipathing and/or load balancing in a
configuration that is specific to a particular disk array.
◆ Integration with other discovery agents such as Storage Area Network (SAN) Access Layer
(SAL) and VERITAS Array Integration Layer (VAIL).
◆ Previous releases of VxVM supported two naming schemes: OS-Native Scheme and
Enclosure-based Naming. Although VxVM provided the means of changing between the two
schemes dynamically, it was necessary to restart vxconfigd which is a time-consuming
operation. With this release, the vxconfigd restart operation is no longer necessary.
◆ VxVM now supports persistent device names. The disk names, once assigned, will remain
constant across reconfiguration and rebooting.
◆ Device discovery is now multi-threaded.
Elimination of rootdg as a Special Disk Group
In previous versions of VxVM, a disk group with the name rootdg (root disk group) was
required. This disk group had special properties, and often acted as the default disk group when a
disk group had not been specified. For VxVM to function, the rootdg disk group had to exist, and
it had to contain at least one disk. This release of VxVM does not require a rootdg disk group to
be present on the system. You may find it convenient to create a system-wide default disk group,
which need not be named rootdg.