<s>
NEC	B-General_Concept
HYDRAstor	I-General_Concept
is	O
a	O
disk-based	B-Device
grid	O
storage	O
system	O
with	O
data	B-General_Concept
deduplication	I-General_Concept
for	O
backups	B-Protocol
and	O
archiving	B-Application
,	O
developed	O
by	O
NEC	O
Corporation	O
.	O
</s>
<s>
A	O
HYDRAstor	B-General_Concept
storage	O
system	O
can	O
be	O
composed	O
of	O
multiple	O
nodes	O
,	O
starting	O
from	O
one	O
up	O
to	O
100+	O
nodes	O
.	O
</s>
<s>
Each	O
node	O
contains	O
standard	O
hardware	O
including	O
disk	B-Device
drives	I-Device
,	O
CPU	O
,	O
memory	O
and	O
network	O
interfaces	O
and	O
is	O
integrated	O
with	O
the	O
HYDRAstor	B-General_Concept
software	O
into	O
a	O
single	O
storage	O
pool	O
.	O
</s>
<s>
HYDRAstor	B-General_Concept
software	O
incorporates	O
multiple	O
features	O
of	O
distributed	O
storage	O
systems	O
:	O
content-addressable	B-Data_Structure
storage	I-Data_Structure
,	O
global	O
data	B-General_Concept
deduplication	I-General_Concept
,	O
variable	O
block	O
size	O
,	O
Rabin	B-Algorithm
fingerprinting	I-Algorithm
,	O
erasure	O
codes	O
,	O
data	O
encryption	O
and	O
load	O
balancing	O
.	O
</s>
<s>
HYDRAstor	B-General_Concept
project	O
was	O
started	O
in	O
2002	O
by	O
Cezary	O
Dubnicki	O
and	O
Cristian	O
Ungureanu	O
in	O
NEC	O
Research	O
in	O
Princeton	O
,	O
NJ	O
.	O
</s>
<s>
After	O
another	O
3	O
years	O
of	O
development	O
,	O
first	O
version	O
of	O
HYDRAstor	B-General_Concept
was	O
brought	O
to	O
the	O
market	O
in	O
US	O
and	O
Japan	O
.	O
</s>
<s>
HYDRAstor	B-General_Concept
can	O
be	O
scaled	O
from	O
single	O
node	O
to	O
165	O
nodes	O
in	O
a	O
multi-rack	O
grid	O
appliance	O
.	O
</s>
<s>
HYDRAstor	B-General_Concept
supports	O
online	O
expansion	O
,	O
with	O
automatic	O
data	O
migration	O
and	O
with	O
no	O
downtime	O
.	O
</s>
<s>
In	O
standard	O
configuration	O
,	O
HYDRAstor	B-General_Concept
provides	O
resiliency	O
to	O
up	O
to	O
3	O
concurrent	O
disk	B-Device
or	O
node	O
failures	O
.	O
</s>
