VxVM

So here I am , having got a chance to work with VxVM in depth. I thought of sharing some concepts I understood so far. It could have minor mistakes .....

As I am very comfortable working on LVM ( like most SAs ) , I think it makes more sense to compare them to the new product.

Basically VXVM offers a number of features than the LVM of AIX or HPUX or that of SuSE Linux. I am not too sure if customers make use of them these days. The reason being, I see most of those features are now done at the storage level saving CPU cycles on your production systems.

LVM :-

LVM is probably the most straight forward product in the Volume Manager family.

PV - Physical Volume - Physical Disk - hdiskX (AIX) , cXtXdX (HPUX & SuSE)
VG - Volume Group - Group of PVs - vgXX (AIX) , /dev/vgXX (HPUX & SuSE)
PV/PE - Physical extents - VG is split into extents.
LP/LE - Logical extents - Once a PE/PP is allocated to an LV you call them LP/LE
LV - Logical Volume - A slice of the VG made of PE/PPs - lv01 ( AIX) /dev/vgXX/lvolXX ( HPUX & SuSE )

Now , you could place a filesystem on the LV or you could use it RAW.

At the storage level you could perform some of the most useful functions that any SA would die to have. Like ,

migrate PE/PPs from a disk to another online.
Add a PV onto volume group and extend / reduce an LV online [ with a supporting jfs if you have filesystem on that]


VXVM :-

VM Disk - A Physical Disk
Subdisk - A partition on a disk , something similier to the PEs / PPs
Plex - Atleast made of one subdisk
Volume - Made of a plex , if you have two plexes you are mirrored. ( I could be wrong here )

Now we can format the volume and mount it to use as a filesystem.

I will add more about VxVM Soon ... Catch you later.