Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Managing Disks and Files
Managing Disks
Chapter 6 567
Using Disk I/O Interfaces
LVM supports disks that use SCSI, HP-FL, and, to a limited extent,
HP-IB I/O interface types, as shown in Table 6-1.
Although the table shows that mixed HP-FL and SCSI disks can belong
to the same volume group, for best performance, you should keep them in
separate groups, each containing identical model disks; that is, each
should have the same characteristics such as size and rotational speed.
HP-IB disks cannot be mixed with the other types.
NOTE LVM can be used on all Series 700 and 800 supported disks.
HP-IB disks are not supported on Series 700 systems.
Bad Block Relocation
If as a result of a defect on the disk, LVM is unable to store data, a
mechanism is provided to store it at the end of the disk. If your disk
supports automatic bad block relocation (usually known as “hardware
sparing”), then LVM’s bad block relocation mechanism is unnecessary.
Bad block relocation is in effect by default when a logical volume is
created. You can use the -r n option of lvcreate (1M) to disable the bad
block relocation feature.
NOTE Bad block relocation is not supported for root, swap, or dump logical
volumes, or on physical volumes larger than 256GB.
Table 6-1 Disk Interface Types and LVM Support
SCSI HP-FL HP-IB
Support mixing of disks with other
interface types within the same
volume group?
Yes Yes No
Support bad block relocation? Yes Yes No
Support LVM mirroring? Yes Yes No