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

Workaround
When a file system is mounted, VxFS keeps certain data structures in the kernel. As the size
of the file system increases, the amount of data structures stored by VxFS also increases. The
file system typically keeps approximately 128 bytes per allocation unit (32,768 file system
blocks). This translates to a usage of 512K per 1 TB for an 8K block size file system (4 MB
per 1 TB for a 1K block size file system). Therefore, large file systems must be mounted only
on systems that have sufficient memory. The memory requirements for mounting large file
systems are shown in the tables below.
Table 1-4 Memory Usage for a File System With a 1K Block Size
256 TB64 TB8 TB1 TB128 GBFile System Size
N/AN/A32 MB4 MB1 MBMemory Usage
Table 1-5 Memory Usage for a File System With a 2K Block Size
256 TB64 TB8 TB1 TB128 GBFile System Size
N/A128 MB16 MB2 MB512 KBMemory Usage
Table 1-6 Memory Usage for a File System With a 4K Block Size
256 TB64 TB8 TB1 TB128 GBFile System Size
128 MB32 MB4 MB512 KB128 KBMemory Usage
Table 1-7 Memory Usage for a File System With an 8K Block Size
256 TB64 TB8 TB1 TB128 GBFile System Size
128 MB32 MB4 MB512 KB128 KBMemory Usage
While performing a full fsck, the system keeps certain data structures in the core for
validating the space usage and inode usage. The space needed depends on the number of
inodes and the number of blocks in the file system. The fsck command needs approximately
16 MB per 1 TB for an 8K block size file system (128 MB per 1 TB for a 1K block size file
system) and 32 MB per million inodes. Sufficient memory and swap space should be
configured on the system before running a full fsck on a large file-enabled system.
A replay of the fsck command does not need a significant amount of memory and does
not have these issues.
• Problem
Some disk quota operations do not function on NFS.
Workaround
When VxFS file systems are exported via NFS, quotas on the file system apply to users when
accessing the file system from NFS clients. However, the HP-UX quota command on the
NFS client cannot be used to edit quotas. The VxFS quota command must be used on the
server to edit quotas.
• Problem
CDS does not support converting the external quota file.
Workaround
20 Veritas File System 5.0 Release Notes