SUMMARY: VxFS vs VxVM

Original post:
> What is a difference between VxFS and VxVm ?
> What is functionality/purpose of each above ?
> Any documents about it ?


Thank you to following people:

Riddoch, John E SITI-ITDS
Espen Martinsen
Firmin, Julie
Nathan Dietsch
Mohammed Al Shammari (Con
sunsrv@blr.cmc.net.in
Rick McKinney
Beavers, Reginald
Steve Mickeler
Jason Wood
Trinh, Linh T. [C]
ed@the7thbeer.com
McCaffity, Ray
Donaldson, Mark
M. Barnabas Luntzel
David Foster
Stephen Barnett
Johan Hartzenberg
Matt Harris

Also thanks to sending me 'sunmanagers-before-posting' but
in sunmanagers archive I did't find any such 'comprehensive short'
comparison of VxFS and VxVM.
Below are answers:

==========================================================================

VxFS: this is the filesystem, in the same way as UFS is a filesystem.  It's
got a few add-ons that make it better than UFS (e.g. grow/shrink on the fly,
change inode density etc).
VxVm: this manages the space on the disks for filesystems to reside on, in
the same way as Disksuite/LVM and, to a certain extent, the format command.
It's better than those because it supports the resizing of filesystems and
other features.

You could, technically, use VxFS on a raw slice on a disk or use UFS on a
VxVm managed volume.

==========================================================================

Veritas Filesystem /VxFS is a filesystem   (like "ufs")
veritas Volume Manager is a volume-manager (like disksuite)

==========================================================================

vxvm is a disk-management tool and vxfs is a file system tool.
Vxvm enables you to mirror data across hardware and vxfs speeds up
the time it takes to construct file systems across said hardware.
You would install vxvm then vxfs so that the two work together.
I suggest you check out

http//www.veritas.com

and you will find more info.

==========================================================================

VxVM is a volume manager. That means you can create so called virtual
disks (Volumes) using various RAID Techniques, ie Mirroring, Striping,
RAID 5.
VxFS is an extent based File System which is sold by Veritas. Rumoured
to be quicker than standard UFS, has many features for databases.

As for Documents go to support.veritas.com and search the knowledge base.

==========================================================================

VxFS is Veritas file system, some thing like UFS(Unix file syetm) like you
do newfs /dev/rdsk/c0t0d0s0, you do nfs /dev/vxfs/...

VxVm is Veritas Volume manager, some thing like you DiskSuite which is
used to Configure RIAD 0,1,5

A combination of VxFS and VxVm will be some thing good.

==========================================================================

VxFS = Veritas File System
VxVM = Veritas Volume Manager

VxFS = Alternative File System
VxVM = way to manage both UFS and VxFS file systems

VxVM
http://www.veritas.com/products/category/ProductDetail.jhtml?productId=volumeman+agerwin


VxFS
http://www.veritas.com/products/category/ProductDetail.jhtml?productId=filesyste+m

==========================================================================

Both are Veritas products.
VxFS is a file system as is UFS, FAT32, NTFS...
VxVM is a volume manager. It is used to create volumes that are presented to
the OS as disks. It allows you to stripe, mirror, etc.

support.veritas.com
[online documentation]
[foundation suite]
[volume manager for unix] or [filesystem for unix]

==========================================================================

FS = High performance file system

VM = volume manager for managing/resizing volumes.
==========================================================================
VxFS is the File System and VxVM is the Volume Manager. The volume manager is
what looks after disk partitioning and that can use either VxFS or UFS as the
file system but it works much better with VxFS. Generally you buy the two
products as a package called Veritas Foundation Suite.
==========================================================================
VxVM only can increase the filesystem size
VxFS can increase and DECREASE filesystem size
==========================================================================
In the most basic sense:

VxFS - the file system, like UFS, HFS, JFS.  It is extents based if I
remember correctly.

VxVm - the Veritas volume manager, used to manage volumes formatted with
the VxFS file system.
==========================================================================
One is volume manager, one is file system.
Veritas is very closed about free documentation.
Sites have been closed and shut down because
of giving out this type of info.
==========================================================================
VxVM is a Logical volume manager.  It virtualizes storage allowing you to
create software mirrors/R5, etc.  It allows you to create logical storage
disks that span more than one physical disk and create more filesystems per
disk than standard slices allow.  It allows you move data between drives
while keeping the filesystem up & hot.

VxFS is a filesystem structure like UFS, JFS, etc.  It's a journaled
filesystem and is usually much faster than UFS for disk intensive
operations.  (we saw a 4x increase in application speed for one highly disk
intensive application on VxFS over UFS).

The two together are cooperative allowing you to easily resize filesystems
both up & down.  They also do some self-tuning when the two are used
together.
==========================================================================
VxFS denotes the filesystem that Veritas offers, thats all. VxVM is the
Volume Manager, the set of tools that manipulates RAID levels and disks
and disk groups and plexs etc etc
==========================================================================
Check out docs.sun.com for documents, and SunSolve Blueprints.

As for comparisons, check the archives of this list, this
question gets asked (and answered) about once a month.
==========================================================================
VxFS is Veritas File System
VxVM is Veritas Volume Manager - allows you to group disks, create RAID
sets, mirrors etc. The only advantage that I found it top have over Sun's
DiskSuite is that it does not use the disk partition table so you can have
more than 7 file systems per disk (with the size of disks these days this
can be a God send).
==========================================================================
VM manages "volumes".  A volume is a virtual device as well as a raw
device, on which you can create a file system.  You can create UFS of VXFS
or other file-systems, or use volumes for RAW database partitions, eg as
used by oracle.

A Volume is essentially a managed bunch of disk blocks.  VXVM gives you
functionality to move them, re-layout volumes, (eg from raid-5 to mirror),
add LOGs, re-size them, etc, on the fly.  Obviously the main advantage of a
volume over a disk slice is that it can span multiple disks and you can
have many on a single disk (not limited by nr of slices).  Also a volume
does not have to have all of it's blocks in a contiguous area, it can be
dispersed across a bunch of disks, using a few blocks here, a couple of
cylinders there, etc.

A File-system is the way UNIX addresses files in a disk device.  It
organises I-nodes and their relevant data blocks into cylinder groups and
manages disk blocks allocated to each individual file.  Normally a
disk-slice, or disk-partition is used to create a file-system.  You can
create a file system in a Volume created by Solstice Disk Suite, or Veritas
Volume Manager, or other competing products.  Veritas File-system allows
you to re-size a mounted file-system on the fly, has got brilliant logging,
and uses Dynamic I-nodes, so you can never run out of i-nodes.  UFS has got
logging as well from Solaris 8 onward, and can be "grown" but not shrinked
(and I don't know if it can be done while the file system is mounted).

You can have logging at both the file-system and the volume level.  FS
logging gives you protection at a per-"transaction" basis, eg every file
system operation must complete before the transaction is committed.  It
allows for very very fast fsck.

In Veritas Terms, a volume can contain a file system.  To grow a file
system, you must first grow the volume.  (The gui does this automatically,
but I hate gui's)

==========================================================================
One is a file system.  The other is volume management [software raid].
Talk to a Veritas account rep or support tech for more info or pre-sales
engineering support.
==========================================================================
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