<s>
Google	B-Application
File	I-Application
System	I-Application
(	O
GFS	B-Application
or	O
GoogleFS	B-Application
,	O
not	O
to	O
be	O
confused	O
with	O
the	O
GFS	B-Application
Linux	B-Operating_System
file	O
system	O
)	O
is	O
a	O
proprietary	B-Application
distributed	B-Protocol
file	I-Protocol
system	I-Protocol
developed	O
by	O
Google	B-Application
to	O
provide	O
efficient	O
,	O
reliable	O
access	O
to	O
data	O
using	O
large	O
clusters	O
of	O
commodity	B-Device
hardware	I-Device
.	O
</s>
<s>
Google	B-Application
file	I-Application
system	I-Application
was	O
replaced	O
by	O
Colossus	B-Application
in	O
2010	O
.	O
</s>
<s>
GFS	B-Application
is	O
enhanced	O
for	O
Google	B-Application
's	I-Application
core	O
data	O
storage	O
and	O
usage	O
needs	O
(	O
primarily	O
the	O
search	B-Application
engine	I-Application
)	O
,	O
which	O
can	O
generate	O
enormous	O
amounts	O
of	O
data	O
that	O
must	O
be	O
retained	O
;	O
Google	B-Application
File	I-Application
System	I-Application
grew	O
out	O
of	O
an	O
earlier	O
Google	B-Application
effort	O
,	O
"	O
BigFiles	O
"	O
,	O
developed	O
by	O
Larry	O
Page	O
and	O
Sergey	O
Brin	O
in	O
the	O
early	O
days	O
of	O
Google	B-Application
,	O
while	O
it	O
was	O
still	O
located	O
in	O
Stanford	O
.	O
</s>
<s>
It	O
is	O
also	O
designed	O
and	O
optimized	O
to	O
run	O
on	O
Google	B-Application
's	I-Application
computing	O
clusters	O
,	O
dense	O
nodes	O
which	O
consist	O
of	O
cheap	O
"	O
commodity	O
"	O
computers	O
,	O
which	O
means	O
precautions	O
must	O
be	O
taken	O
against	O
the	O
high	O
failure	O
rate	O
of	O
individual	O
nodes	O
and	O
the	O
subsequent	O
data	O
loss	O
.	O
</s>
<s>
A	O
GFS	B-Application
cluster	O
consists	O
of	O
multiple	O
nodes	O
.	O
</s>
<s>
The	O
changes	O
are	O
not	O
saved	O
until	O
all	O
chunkservers	O
acknowledge	O
,	O
thus	O
guaranteeing	O
the	O
completion	O
and	O
atomicity	B-General_Concept
of	O
the	O
operation	O
.	O
</s>
<s>
no	O
outstanding	O
leases	O
exist	O
)	O
,	O
the	O
Master	O
replies	O
with	O
the	O
locations	O
,	O
and	O
the	O
program	O
then	O
contacts	O
and	O
receives	O
the	O
data	O
from	O
the	O
chunkserver	O
directly	O
(	O
similar	O
to	O
Kazaa	B-Protocol
and	O
its	O
supernodes	B-Protocol
)	O
.	O
</s>
<s>
Unlike	O
most	O
other	O
file	O
systems	O
,	O
GFS	B-Application
is	O
not	O
implemented	O
in	O
the	O
kernel	B-Operating_System
of	O
an	O
operating	B-General_Concept
system	I-General_Concept
,	O
but	O
is	O
instead	O
provided	O
as	O
a	O
userspace	B-Operating_System
library	O
.	O
</s>
<s>
The	B-Application
Google	I-Application
File	O
System	O
does	O
not	O
provide	O
a	O
POSIX	O
interface	O
.	O
</s>
<s>
It	O
supports	O
Record	O
Append	O
which	O
allows	O
multiple	O
clients	O
to	O
append	O
data	O
to	O
the	O
same	O
file	O
concurrently	O
and	O
atomicity	B-General_Concept
is	O
guaranteed	O
.	O
</s>
