Veritas 4.1 Installation Guide (HP-UX 11i v3, February 2007)

exposed to file server and web server loads, or when the file system performance is not critical,
may not require a large inode cache. In such cases, vx_ninode can be tuned down by hand. It
is recommended to use the following table to tune vx_ninode to a minimum value based upon
memory size. HP recommends that you set a minimum value as specified below based upon the
memory configuration.
Table A-2 Physical Memory Vs. VxFS Inode Cache Size
VxFS inode cache (number of inodes)
1
Physical Memory or Memory in Base Cells in GB
163841.5
327682
655363
131072> 3GB
1 Note that the default values are set at boot time and the values are not automatically adjusted when memory is
added/removed/migrated at run time.
Controlling the Buffer Cache
VxFS 4.1 implements a private buffer cache used exclusively for metadata. The allocations made
for this buffer cache are not static but grow and shrink with usage, depending on the load on
the file system. The global (dynamic) tunable vxfs_bc_bufhwm represents the maximum possible
size of the VxFS buffer cache. The maximum size of the metadata buffer cache is set
(auto-tuned
1
) based on the system memory configuration, provided that the value of
vxfs_bc_bufhwm is set to zero (default). This is similar as in the case of the tunable vx_ninode,
a large metadata buffer cache can help improve file system performance, especially during
metadata-intensive loads (stat, create, remove, link, lookup operations). Systems with relatively
low total RAM or relatively low in memory base cells (typically 1.5 GB) normally do not need a
large metadata buffer cache if the file system load is not metadata-intensive or when performance
is not critical. In such circumstances, the value of vxfs_bc_bufhwm can be manually tuned
down, subject to a minimum of 6 MB.
LVM Volume Groups to VxVM Conversion Error Messages
The following errors may occur during conversion of LVM volume groups To VxVM disk groups:
• Analysis indicates that this volume group cannot be converted because not all of the disks and/or
volumes in the LVM volume group are currently accessible
— Description
For successful conversion, all physical volumes in a volume group must be on-line, and
all logical volumes must be active and accessible.
— Action
Make sure the physical volumes in a volume group are on-line and the logical volumes
are active and not in use.
• Analysis shows that there is insufficient private space available to convert this volume group
— Description
The error message indicates the maximum amount of records that can be stored in the
private space, and how many records are needed to convert this particular volume
group.
— Action
You can reduce the number of records needed by reducing the number of logical volumes
in volume group by combining some of the logical volumes together.
1. The auto-tune values are calculated at boot time, as well as during an event that adds/removes/migrates memory
during run time.
72 Appendix