Sun Microsystems Virtual Tape Library - Manual (Page 18)

Advantages of VTL tape virtualization
4 VTL User Guide • May 2008 G • 96267
Advantages of VTL tape virtualization
Adding Sun StorageTek VirtualTape Library appliances to an existing tape‐based
backup architecture can thus realize the following advantages:
■
“Shorter runtimes and reduced dependency on backup windows” on page 4
■ “Shorter run times for non‐sequential backup jobs” on page 5
■
“Improved reliability” on page 5
■
“Better utilization of tape subsystems” on page 5
■ “Larger, more flexible libraries” on page 6
■
“Compatibility with ACSLS management software” on page 6
■
“True tape virtualization with dynamically allocated disk space” on page 7.
Shorter runtimes and reduced dependency on
backup windows
VTL appliances can handle a narrow backup window by using numbers of virtual
drives operating in parallel, something that would be highly impractical with
physical tape drives. In this way, the critical, first copy of the primary data is reliably
transferred to disk‐based virtual tape in minimum time. Thereafter, vaulting
software and/or VTL tape‐caching features can copy the backup from virtual to
physical media using a smaller, more economical number of physical drives. See the
figure below:
Multiple virtual drives speed backup during the critical backup window
virtual
tape
drives
virtual library physical library
primary storage
physical
tape
drives
Back up to multiple virtual tape
drives during the critical
backup window At other times, copy virtual tapes to
physical media using one or two
dedicated tape drives
backup
window