Here's an excerpt from the Sun web page (www.sun.com) regarding VERITAS:
VERITAS Volume Manager software is an advanced, system-level disk and storage array solution that alleviates downtime during system maintenance by enabling easy, online disk administration and configuration. The product also helps ensure data integrity and high availability by offering fast failure recovery and fault tolerant features. VERITAS Volume Manager software provides easy-to-use, online storage management for enterprise computing and emerging Storage Area Network (SAN) environments. Through the support of RAID redundancy techniques, VERITAS Volume Manager software helps protect against disk and hardware failures, while providing the flexibility to extend the capabilities of existing hardware. By providing a logical volume management layer, VERITAS Volume Manager overcomes the physical restriction imposed by hardware disk devices.
So, there you have it. But let me briefly list some of the things they totally missed.
Support for: Simple, RAID0, RAID1, RAID0+1, RAID1+0, RAID5
Dynamic Multipathing (DMP): Load balancing and redundant I/O paths to disk arrays supporting multi-controller attachment.
Online Relayout: VERITAS allows you to change the layout of a VERITAS volume while it is live and mounted. Change a RAID0 to a RAID5 without a second of downtime!
Snapshoting: Take a snapshot of your data, creating a "shadow" of it which you can use for online backups.
Hot Relocation: Designate "spares" which will take the place of failed disks on-the-fly.
Dirty Region Logging (DRL): Volume transaction logs which provide fast recoveries after system crashes.
More...... more than I can list!
So lets start by building on all that. VERITAS Volume Manager is a product of VERITAS Software Corporation (www.VERITAS.com), which is used by Sun and also sold to Sun customers under a Sun part number. VERITAS is also can "Vx" or "VRTS" (the prefix of VERITAS packages, and VERITAS' ticker symbol). VERITAS Volume Manager is often abbreviated "VxVM". Sun, before VERITAS 3.x, had its own marketing names for VERITAS, the names you'll see and the version numbers are:
<= Vx 2.5: Sun Enterprise Volume Manager (SEVM)
= Vx 2.6: Sun StorEdge Volume Manager (Sun SEVM)
> Vx 3.x: VERITAS Volume Manger (VxVM)
As for OS support:
SEVM 2.5: Solaris 2.5.1 and older.
SEVM 2.6: Solaris 2.6 and Solaris 2.5.x
VxVM 3.0.2: Solaris 7, Solaris 2.6, and Solaris 2.5.x
VxVM 3.0.3: Solaris 8, Solaris 7, and Solaris 2.6
Let me add, when Sun and/or VERITAS says "OS xxx isn't supported", they don't really mean "Ummm, we haven't really tried it yet", like most other companies in the world. VERITAS actually installs kernel modules into the system, so if you run SEVM 2.6 on Solaris 7, you'll be running Solaris 2.6 kernel modules in a Solaris 7 kernel. It doesn't work, I tried it! (and Sun was really pissed when they found out I tried it )