For 10.10, the maximum size of HFS and JFS file systems has
been increased from 4 Gb to 128 Gb. (The maximum size of files continues
to be 2 Gb.)
Large file systems are supported by HP-UX, including file
system administration commands (HFS and JFS), SAM, SD, LVM, accounting
commands, quota commands, and backup commands. These interfaces,
as in previous releases, allow you to create, modify, and recover
file systems. All of the command interfaces remain the same; there
are no new options for large file systems. The only difference is
the parameter values may now be larger to accommodate file systems
greater than 4 Gb.
Large file systems can be exported through NFS to other clients,
who are be on any other supported version of HP-UX. NFS clients
do not have to be on 10.10 to read/write an exported file system.
For example, a 10.10 server can export a 20 Gb file system to 9.x
clients through NFS and each of the clients can read/write to the
20 Gb file system. Non-HP NFS clients can also access an LFS on
an HP server.
Making Small File Systems Large |
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Increasing the size of a small file system to a large file
system is supported through the standard file system extension command
extendfs(1M).
Using extendfs
for JFS is new for HP-UX 10.10. An alternative to extendfs
is to back up the data, remake the file system, and restore the
data.
Compatibility with pre-10.10
Filesystems |
|
All file systems built with earlier versions of HP-UX are
fully supported in 10.10. There is no conversion required of pre-10.10
file systems to be functional in 10.10.
Limitations |
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It is not possible to use large file systems for root or boot
disks because there are limitations of 2 Gb or 4 Gb (depending on
the processor) in the IODC.
Applications that access devices directly will continue to
have a 4 Gb limit. There is no interface for large devices. The
implementation is for large file systems only and is supported through
the standard set of administration commands mentioned above.
It is possible for users to access file systems directly through
their respective device files. The contents can be copied with cp(1)
or displayed with od(1).
This usage is rare and will continue to be limited to 4 Gb. An exception
to this is dd(1),
which will support large file devices.
Performance |
|
For 10.10, there should be no performance degradation. Building
and recovering (using fsck)
a very large HFS file system will take proportionately longer than
a smaller system. For a JFS file system, the scaling is proportional
to the log size, not the file system size. Random access performance
on both file systems is not impacted.
dcopy Command |
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The dcopy
command has not been enhanced to support large file systems, but
will continue to operate on small file systems. All other commands
and interfaces remain intact.
fsirand |
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fsirand
supports the lseek()
block modifications for large file systems. If fsirand
detects a large file system, all lseek()
calls must use block or byte offsets.
Previous versions of fsirand
will not work properly on a large file system. The current 10.10
version of fsirand
should not be run on a previous release.
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