sds (kinda) work by remzi's group and others

use flash as a cache (from mike swift's group)
flash is widely used as cache
use ssd's block interface is inefficient for cache, because cache is different from storage
new firmware in ssd, to get rid of block mapping, and use unified address space
they also provide consistent cache interface (which blcok is clean/dirty, which block has been evicted, etc.)
when doing gabage collection, don't have to migarate because it's cache, and we have primary copy of the data somewhere
we plan to propose new interfaces and virtual ssds (so it could be more software defined???)

combating ordering loss in the storage stack -- the no-order fs work (Vijay)
ordering not respected in many layers
don's use ordering to ensure consistency
1. coerced cache eviction -- additional write to flush cache to ensure ordering
2. backpointer-based consistency, do verification on backpointers when following pointers in file systems
3. (on going) inconsistency in virtualized storage setting

de-virtualization for flash-based ssd (yiying) - the nameless writes in ssd
take off too many layers of block mappings in file system -TFL- physical block
store physcial block number directly in file systems (when file system write a block, no position is specified, and disk decide where to put the block, and inform file system where the block got written)

in a virtualized enviormant: file system de-virtualizer (on going, i think)
file system perform normal writes, but fsdv do nameless writes, and store physical mapping)


zettabyte reliability (yupu)
add checksum at file system/memory bondaries
also an analytical framework to reason about reliability -- the sum of probability model
future: data protection as a service? without modifications to the os? i am not quite sure how to realize this....)

low latency storage class memory
data-centric workloads are sensitive to storage latency
storage-class momory: phase-change memory, stt-ram etc.): persistent, low latency, byte addressable
mnemosyne: persistent regions + consistency
                     persistency: so that data structures don't get corrupted
                     consistency: update data in a crash-safe way


Harden HDFs( Than Do)
software defined way to ensure system reliability
1. selective 2-versioning programming
2. encode file system states using bloom filters