Veritas File System 5.0 Release Notes, HP-UX 11i v3, First Edition, May 2008

Tuning VxFS for Performance
• Tuning down the inode cache
VxFS allocates and releases inodes based on the file system load. Generally, larger inode
caches help the file system to perform better in the case of a file server or web server load.
The global tunable, vx_ninode, determines the maximum possible size of the VxFS inode
cache. If the default value of vx_ninode is set to zero, VxFS automatically tunes the size
of the inode cache at boot time, based on the size of the physical memory on the system. On
systems with a RAM size of less than or equal to 1 GB, you can manually tune down
vx_ninode to a value not less than that of ninode (nfile is an HP-UX tunable that
represents the maximum number of file descriptors). If the user does not manually tune the
value of vx_ninode then VxFS calculates vx_ninode value based on system memory.
VxFS ensures that the value of vx_ninode is not less than ninode. For more information
on these commands, see vx_ninode(5).
• Tuning down the buffer cache
VxFS 5.0 implements a private buffer cache to use exclusively for metadata. The allocations
to this buffer cache vary during system usage based on the file system load and the maximum
cache size specified in the global (static) tunable, vxfs_bc_bufhwm. If the value of
vxfs_bc_bufhwm is set to zero, VxFS automatically tunes the maximum size of the metadata
buffer cache at boot time, based on the system memory size. On systems with a RAM size
of 1 GB or less, you can manually tune down the value of vxfs_bc_bufhwm to a minimum
of 6144 (6 MB). If the user does not manually tune the value of vxfs_bc_bufhwm then VxFS
calculates vxfs_bc_bufhwm value based on system memory. VxFS ensures that the value
of vxfs_bc_bufhwm is not less than 800 KB.
For more information on tuning VxFS, see the following documents available at:
http://docs.hp.com
Common Misconfigured HP-UX Resources
Veritas File System 5.0 Administrator’s Guide
NOTE: VxFS consumes a fixed percentage of memory for storing the default values of tunables,
such as vx_ninode and vxfs_bc_bufhwm. For example, VxFS consumes nearly 10% of total
physical memory for the default value of vx_ninode. If the system has 512 MB of memory,
VxFS will require up to 52 MB to store the VxFS inode cache. Therefore, it is necessary to tune
the tunables according to the type of the load on the system.
System Requirements
The following section discusses the OS Version supported and the patches required for VxFS 5.0
on HP-UX 11i v3.
• OS Version
HP-UX 11i v3.
• Required Patches
For information on the required and recommended patches, see Veritas 5.0 Installation Guide
HP-UX 11i v3.
Product Licensing
• HP OnlineJFS
The following features are enabled by the HP OnlineJFS license:
12 Veritas File System 5.0 Release Notes