Differnt filesystems in HPUX

[Badri]

Hi

Please share if there an comparison available for different file systems that are used in HPUX...

LVM (HFS, JFS, online JFS, VXFS)

VXVM

Thanks
Badri

[Michael Steele_2]

LVM stands for logical volume manager. It is in between the physical layer (* disks *) and the file system layer. HFS stands for Hi Performance File system and is mostly obsolete after HP-UX 10.20. You now only see it used in / (*root*) and /stand (*kernel *). JFS stands for Journal File System. Although there is a Base JFS made by veritas I don't think JFS is meant to refer to Base JFS only. JFS could be either BASE or Online JFS. Online JFS, also made by veritas, is the standard HP-UX file system utility of choice. You have to get a license to use it. It provides dynamic file system changes not provided in HFS. For example, increase the size of a file system without unmounting. It also provides for defragmentation, also something HFS doesn't provide, however, some experts will tell you that HFS doesn't need to be defragmented.

HFS Supported Sizes
===================
The maximum file and filesystem sizes supported by HFS are listed in the
table below.

TABLE 1. HFS Supported File and File System Sizes
====================================
HP-UX File Filesystem
Release Size Size
====================================
10.01 2 GB 4 GB
10.10 2 GB 128 GB
*10.20,11.x 128 GB 128 GB
====================================

* On these releases it is possible to exceed the 128 GB limit to 256
GB, but it is not supported.

JFS (VxFS) Supported Sizes
==========================
The maximum file and file system sizes supported by the Journaled File
System (JFS), also known as the VERITAS File System (VxFS), are listed in
the table below.

VxFS Supported File and Filesystem Sizes
==============================================================
HP-UX JFS Disk Layout File Filesystem
Release Version Version Size Size
==============================================================
10.01 - Version 2** 2 GB 4 GB

10.10 - Version 2** 2 GB 128 GB

10.20 Version 3.0 Version 2 2 GB 128 GB
10.20 Version 3.0 Version 3** 128 GB 128 GB

11.00 Version 3.1 Version 2 2 GB 128 GB
*11.00 Version 3.1 Version 3** 1 TB 1 TB

11.00 Version 3.3 Version 2 2 GB 128 GB
11.00 Version 3.3 Version 3** 1 TB 1 TB
11.00 Version 3.3 Version 4 1 TB 1 TB

11i Version 3.3 Version 2 2 GB 128 GB
11i Version 3.3 Version 3 2 TB 2 TB
11i Version 3.3 Version 4** 2 TB 2 TB
11i v2.x Version ? Version ? 4 TB 4 TB
==============================================================

There are also NFS, (network file system, developed by SUN) and raw file system. Many database prefer a raw file system access to increase speed and eliminate the overhead vxfs or hfs would cause.

[Badri]

Thanks Mike for sending useful information, could you share the differences between VXVM and LVM?

[inventsekar_1]

HPUX offers 3 different approaches for creating and managing disk partitions.

1. Whole Disk approach
2. LVM (Logical volume manager)
3. VXVM (Veritas Volume Manager)(only from 11i)

attached file for the differences between these three methods.

[James R. Ferguson · Accepted solution]

Hi Badri:

FIrst, LVM and VxVM are disk *volume* management software. A very good comparison of the features of both can be found in chapter-1 of the VERITAS Volume Manager Migration Guide:

http://www.docs.hp.com/en/5991-1841/5991-1841.pdf

A concise description of LVM, which many people forget exists, can be found in section-7 of the manpages:

http://www.docs.hp.com/en/B2355-60105/lvm.7.html

HFS, JFS (or VxFS) are two different kinds of *filesystems*. Both HFS and VxFS (JFS) filesystems are supported by LVM and by VxVM.

HFS stands for High Performance File System. It decends from the older UFS (Unix File System).

VxFS (often referred to as "JFS" in HP-UX circles) is Veritas's filesystem in partnership with HP. (As a filesystem it has its roots in IBM's JFS variation). Online JFS merely adds some additional, but highly useful, features to the base JFS (VxFS).

HFS is primarily used for the '/stand' filesystem today since up until 11.23, booting the kernel must occur from an HFS filesystem. The secondary loader needs knowledge of the filesytem to find the kernel code. Adding the knowledge of VxFS filesystem to the loader has not been a high priority nor critical need.

While HFS has not continued to evolve (receive enhancements), it is fast and efficient, particularly for small files that change frequently.

VxFS brings the ability to configure vastly larger filesystems over HFS. Orders of magnitude larger filesystem are supported by VxFS as opposed to HFS. HFS is limited to 128GB while the latest VxFS filesystems will support 32TB.

Inodes are unlimited in VxFS filesystems whereas they are not in HFS ones. VxFS is a jounaled filesystem that logs changes to a circular log before writing them to disk. This makes crash recovery very fast compared to HFS filesystems.

VxFS filesystems support large files well, particularly when the file's size (but not content) don't change. This differs from HFS (see above).

With HP-UX, adding the "Online JFS" license adds the ability to expand or shrink a filesystem without having to unmount it -- something lacking in HFS.

WIth Online JFS, filesystems can be mounted with different options to optimize performance. For instance, some mount options enable I/O to bypass the Unix buffer cache -- useful when primarily writing or when a database management layer is doing buffering anyway. More information about VxFS mount options appears in the manpages for 'mount_vxfs(1M)' among other documents.

Regards!

...JRF...

[Badri]

Sekar there is no attachment.

[Badri]

Thanks James for giving Good pointers...

[inventsekar_1]

i dont know why ITRC forum responding this much slow? is it my computer problem or else?and at times errors while replying and refresh taking so much time.

and attached the VxVM, LVM simple comparison.

The VERITAS File System, or VxFS, is an extent-based file system that was developed by VERITAS Software as the first commercial journaling file system.

The version 5 on-disk layout of VxFS supports filesystems up to 32 terabytes in size. Individual files can be up to 2 terabytes in size. Version 5 was introduced in VxFS 3.5.

from these u can find out how VxVM is advanced than LVM.

something more:
http://en.wikipedia.org/wiki/Logical_volume_management
http://www.cuddletech.com/veritas/
Advanced VxVM Commands
http://eval.veritas.com/downloads/van/avm_quickref.pdf

[inventsekar_1]

hi Badri,
refer these commands man pages also:
newfs mount

and mount -v will give u a output which shows the filesystem type:
---------------------------------------------
mount -v
/dev/vg00/lvol3 on / type vxfs log on Thu May 25 13:37:31 2006
/dev/vg00/lvol1 on /stand type hfs defaults on Thu May 25 13:37:32 2006
/dev/vg00/lvol8 on /var type vxfs delaylog,nodatainlog on Thu May 25 13:37:38 2006
/dev/vg00/lvol7 on /usr type vxfs delaylog,nodatainlog on Thu May 25 13:37:38 2006
/dev/vg01/lvol2 on /u01/app/oracle type vxfs delaylog,nodatainlog on Thu May 25 13:37:38 2006
/dev/vg00/lvol6 on /tmp type vxfs delaylog,nodatainlog on Thu May 25 13:37:39 2006
/dev/vg01/lvol1 on /oradata type vxfs delaylog,nodatainlog on Thu May 25 13:37:39 2006
/dev/vg00/lvol5 on /opt type vxfs delaylog,nodatainlog on Thu May 25 13:37:39 2006
/dev/vg00/lvol4 on /home type vxfs delaylog,nodatainlog on Thu May 25 13:37:39 2006
---------------------------------------------
and this:
---------------------------------------------
fstyp -l
hfs
nfs
cdfs
autofs
ffs
cachefs
nfs3
vxfs
lofs
pipefs
---------------------------------------------

[inventsekar_1]

cdfs is "cd file system". but what about cd and dvd?
is both cd and dvd uses a single file system(cdfs).. if not, how?

[Badri]

Thanks all for the replys.