VERITAS Storage Foundation 4.1 Release Notes

VERITAS Storage Foundation Release Notes
Software Issues
41
Tuning Down the Inode Cache
VxFS file systems allocate and release inodes based on the file system load. Generally, larger inode
caches help the file systems to perform better in the case of a file server or web server load. The
global (static) 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 per CPU, you can manually tune down vx_ninode to a
value not less than that of nfile (nfile is an HP-UX tunable that represents the maximum
number of file descriptors).
Tuning Down the Buffer Cache
VxFS 4.1 implements a private buffer cache to use exclusively for metadata. The allocations to this
buffer cache vary during system usage based on 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 per CPU or less, you can
manually tune down the value of vxfs_bc_bufhwm to a minimum of 6144 (6MB).
100% Full File System Cannot Be Resized
In some circumstances, the fsadm command cannot resize a 100% full file system due to lack of
space for updating structural information. Check VxFS file systems on a regular basis and increase
their size if they approach 100% capacity. If a file system is busy or too fragmented, the resize
operation can also fail.
Setting max_thread_proc Tunable
Setting max_thread_proc to a low value may result in the system being in a hung state. If the
value of this tunable is less than 1100, the value will be automatically set to 1100 when VxFS is
installed. This value must be maintained at or above 1100.
DMAPI dm_get_dirattrs Can Skip Directory Entries
vx_hsm_get_dirattr() reads a directory's dirents 8 KB at a time, if the passed in user buffer
is not large enough to hold the combined entries’ corresponding file stats information (up to
~114kb). Then the next call to vx_hsm_get_dirattr() will continue from the wrong offset
within the directory, resulting in some directory entries being skipped.
Note There is no error indication. The expectation is to continue from the last dirent information
that could fit into the user's buffer. However, the next directory read will begin 8 KB further
down the directory.