Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

Technical Support ............................................................................................... 4
Chapter 1 Understanding Veritas Volume Manager ....................... 19
About Veritas Volume Manager ...................................................... 19
VxVM and the operating system ..................................................... 20
How data is stored .................................................................. 21
How VxVM handles storage management ......................................... 21
Physical objects ..................................................................... 21
Virtual objects ....................................................................... 27
Volume layouts in VxVM ............................................................... 34
Non-layered volumes .............................................................. 34
Layered volumes .................................................................... 35
Layout methods ..................................................................... 35
Concatenation, spanning, and carving ........................................ 36
Striping (RAID-0) ................................................................... 38
Mirroring (RAID-1) ................................................................. 41
Striping plus mirroring (mirrored-stripe or RAID-0+1) .................. 42
Mirroring plus striping (striped-mirror, RAID-1+0 or
RAID-10) ........................................................................ 43
RAID-5 (striping with parity) .................................................... 44
Online relayout ............................................................................ 51
How online relayout works ...................................................... 51
Limitations of online relayout .................................................. 55
Transformation characteristics ................................................ 55
Transformations and volume length .......................................... 56
Volume resynchronization ............................................................. 56
Dirty flags ............................................................................ 57
Resynchronization process ...................................................... 57
Dirty region logging ..................................................................... 57
Log subdisks and plexes .......................................................... 58
Sequential DRL ...................................................................... 58
SmartSync recovery accelerator ............................................... 59
Volume snapshots ........................................................................ 60
Comparison of snapshot features .............................................. 62
FastResync ................................................................................. 63
FastResync enhancements ....................................................... 64
Contents