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