ESS is a software
layer that enhances the capabilities
of a block storage device. ESS works
by applying several techniques.
Block Mapping
ESS re-maps all
writes as 4K pages. Thus any 4K page
can be stored anywhere on the target
block device and ESS knows
immediately where that 4K page is
located.
Linear
Writes
ESS writes data
in controlled linear segments that
are optimized for maximum
performance with both Parity RAID
arrays and Flash block devices.
Flash SSDs, PCI-e cards, nVME
drives, and other flash solutions
all have NAND flash internally. By
writing linearly, ESS off-loads much
of the block management from the
drive to the host. This creates and
environment where the drive sees
only "perfect writes" that can run
at full speed and without the need
to ever reorganize blocks. This
block reorganization, often called
garbage collection, simply never
happens with an ESS controlled
device because ESS writes with
patterns that simply never leave any
garbage behind.
Linear writes
also eliminates overhead created in
Parity RAID arrays. Normally, random
writes to RAID-5 or RAID-6 will
result in 2x or 3x write
amplification. Because ESS writes
perfectly aligned full stripes,
RAID-5 and RAID-6 amplification is
lowered to the theoretical n/(n-1)
or n/(n-2).
Meta
Storage
ESS records
blocks and the control information
that goes with those blocks as
"atomic writes". Being part of an
atomic write means that the data and
control information that goes with
the data (this is called meta data)
is always written together and can
never get out of sync in the case of
a crash. This unique, and patented,
aspect of ESS is largly responsible
for the incredible speed that ESS
delivers with random write
workloads.
Sparse Storage
ESS is, by it's
nature, a sparse storage engine.
When writing, specific patterns are
"recorded" but not actually written.
For example, if you write a 4K
blocks that is all zeros, ESS will
write the meta data for that block,
but will not write an actual block.
This is similar to discard or trim
operations common with SSDs, except
that writing zeros work even across
a wan or when erasing a file.
Compression
ESS can be setup
to compress individual 4K blocks to
save space. Compression can be also
be used to increase the performance
of low bandwidth arrays and to
reduce flash wear by actually
lowering the amount of data
writting. More information is
available on the
compression page.
Deduplication
Deduplication
support is not yet available in ESS
production releases. If you have an
application that can exploit
deduplication, please contact EasyCo
for pre-release information.
ESS can be setup
to perform real-time block-level
deduplication. Wtih deduplication,
blocks are analyzed so that blocks
with identical contents are only
stored once. De-dupe is ideal for
environments with many duplicate
blocks such as hosting many virtual
servers all with the same OS files.
VDI is a prime example of this.
Deduplication can have signifigant
memory and CPU requirements. More
information is available on the
deduplication page.
