User`s guide

write-back
A cache write strategy that writes to the cache memory, the MAY flush the
data to the primary media at some future time. The user sees the operation as
complete when the data has reached the cache. The intent of this strategy is to
avoid unnecessary accesses to the primary media.
write hole
Undetectable RAID level 1 or 5 data corruption. A write hole is caused by the
successful writing of some, but not all, of the storageset members. Write holes
occur under conditions such as power outages, where the writing of multiple
members can be abruptly interrupted. A battery backed-up cache design
eliminates the write hole, because data is preserved and writes can be retried.
write-through cache
A cache write strategy in which the destination of the write data is the primary
storage media. This operation may update, invalidate, or delete data from the
cache memory accordingly, to ensure that the cache does not contain obsolete
data. The user sees the operation as complete only after the backup storage
device has been updated.
Glossary–9