Veritas File System 5.0 Release Notes (September 2006)

Veritas File System 5.0 Release Notes
Known Issues
Chapter 1 19
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 5.0 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 (6 MB).
• 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 fails.
• 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
The vx_hsm_get_dirattr () reads a directory entries 8 KB at a time, if the user buffer is not large
enough to hold the combined entries corresponding file statistics 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 directory
entries information that could fit into the user’s buffer. However, the next directory
read will begin 8 KB farther down the directory. As a workaround this issue can be
avoided by passing a sufficiently large user buffer
• Data integrity issues with disks and disk arrays with write-back caches
Disk drives configured to use a write-back cache, or disk arrays configured with a volatile write-back
cache, exhibit data integrity problems. The problems occur after a power failure, SCSI bus reset, or
other event in which the disk has cached data, but has not yet written it to non-volatile storage. Contact
your disk drive or disk array manufacturer to determine whether your disk drives use a write-back
cache, and if the configuration can be changed to disable write-back caching.
• Under some conditions, fsadm cannot truncate a directory