Thin Provisioning: Nondeterministic Storage Feature #2

Much of modern storage management focuses on efficient use and allocation of storage capacity.  “Thin provisioning” is a primary mechanism for this, allocating just enough space to match each consumer‘s current needs, while promising more capacity when needed.  Thin provisioning is an effective tool for allocation of storage capacity.  When latency, bandwidth and IOPS are more important, thin provisioning makes these performance results nondeterministic.  Continue reading Thin Provisioning: Nondeterministic Storage Feature #2

Cache: Nondeterministic Storage Feature #1

Every producer of storage software (including what is hidden inside of “hardware”) has spent years and many engineering hours developing their cache algorithms.  Disks have cache; controllers have cache; subsystems have cache; operating systems have cache.  The better the algorithm is, the better the ratio of cache hits to cache misses.  Ultimately though, the decision of what to have in cache is a guess.  Continue reading Cache: Nondeterministic Storage Feature #1