belt and suspenders
belt and braces
failover
redundancy
fault tolerance
Byzantine fault tolerance
redundant array of independent disks
redundant
fail over
stripe
failback
have two strings to one's bow
restore
liveness
backup
Peterson's algorithm
adoption
critical load
autobackup
image copy
rolling backup
weakest link
backup system
leak
seqlock
fallback
single point of failure
fault-tolerant
shoot one's bolt
garbage collection
barf
systolic array
incremental backup
yo-yo mode
nonrenewable resource
security system
fat client
antiredundancy
lay eggs
selective collection
spare part
disk cache
instability
renew
interoperate
replicatively
fail-safe
lay aside
renewable
compatibility