Robust
Referring to the health, strength and durability of something. In computing terms, being robust is reliability or being available seven days a week, twenty-four hours a day. Robustness is an important characterists of the internet because network design is a key factor in the availability of data.
Examples
A robust file sharing program may not provide all the desired data all the time but will deliver reliably, matching queries and completing downloads.
See also: Programming | Security | Data Haven