<s>
In	O
computer	B-General_Concept
storage	I-General_Concept
,	O
a	O
global	B-Operating_System
file	I-Operating_System
system	I-Operating_System
is	O
a	O
distributed	B-Protocol
file	I-Protocol
system	I-Protocol
that	O
can	O
be	O
accessed	O
from	O
multiple	O
locations	O
,	O
typically	O
across	O
a	O
wide-area	O
network	O
,	O
and	O
provides	O
concurrent	O
access	O
to	O
a	O
global	B-General_Concept
namespace	I-General_Concept
from	O
all	O
locations	O
.	O
</s>
<s>
In	O
order	O
for	O
a	O
file	B-Application
system	I-Application
to	O
be	O
considered	O
global	O
,	O
it	O
must	O
allow	O
for	O
files	O
to	O
be	O
created	O
,	O
modified	O
,	O
and	O
deleted	O
from	O
any	O
location	O
.	O
</s>
<s>
There	O
are	O
a	O
number	O
of	O
benefits	O
to	O
using	O
a	O
global	B-Operating_System
file	I-Operating_System
system	I-Operating_System
.	O
</s>
<s>
First	O
,	O
global	B-Operating_System
file	I-Operating_System
systems	I-Operating_System
can	O
improve	O
the	O
availability	O
of	O
data	O
by	O
allowing	O
multiple	O
copies	O
to	O
be	O
stored	O
in	O
different	O
locations	O
,	O
as	O
well	O
as	O
allowing	O
for	O
rapid	O
restoration	O
of	O
lost	O
data	O
from	O
a	O
remote	O
location	O
.	O
</s>
<s>
Second	O
,	O
global	B-Operating_System
file	I-Operating_System
systems	I-Operating_System
can	O
improve	O
performance	O
by	O
allowing	O
data	O
to	O
be	O
cached	O
closer	O
to	O
the	O
users	O
who	O
are	O
accessing	O
it	O
.	O
</s>
<s>
Finally	O
,	O
in	O
contrast	O
to	O
traditional	O
Network	B-Application
attached	I-Application
storage	I-Application
,	O
global	B-Operating_System
file	I-Operating_System
systems	I-Operating_System
can	O
improve	O
the	O
ability	O
of	O
users	O
to	O
collaborate	O
across	O
multiple	O
sites	O
,	O
in	O
a	O
manner	O
similar	O
to	O
Enterprise	B-General_Concept
file	I-General_Concept
synchronization	I-General_Concept
and	I-General_Concept
sharing	I-General_Concept
.	O
</s>
<s>
The	O
term	O
global	B-Operating_System
file	I-Operating_System
system	I-Operating_System
has	O
historically	O
referred	O
to	O
a	O
distributed	B-Architecture
virtual	O
name	O
space	O
built	O
on	O
a	O
set	O
of	O
local	O
file	B-Application
systems	I-Application
to	O
provide	O
transparent	O
access	O
to	O
multiple	O
,	O
potentially	O
distributed	B-Architecture
,	O
systems	O
.	O
</s>
<s>
These	O
global	B-Operating_System
file	I-Operating_System
systems	I-Operating_System
had	O
the	O
same	O
properties	O
such	O
as	O
blocking	O
interface	O
,	O
no	O
buffering	O
etc	O
.	O
</s>
<s>
but	O
guaranteed	O
that	O
the	O
same	O
path	O
name	O
corresponds	O
to	O
the	O
same	O
object	O
on	O
all	O
computers	O
deploying	O
the	O
filesystem	B-Application
.	O
</s>
<s>
Also	O
called	O
distributed	B-Protocol
file	I-Protocol
systems	I-Protocol
these	O
file	B-Application
systems	I-Application
rely	O
on	O
redirection	O
to	O
distributed	B-Architecture
systems	I-Architecture
,	O
therefore	O
latency	O
and	O
scalability	O
can	O
affect	O
file	B-Application
access	I-Application
depending	O
on	O
where	O
the	O
target	O
systems	O
reside	O
.	O
</s>
<s>
The	O
Andrew	B-Application
File	I-Application
System	I-Application
attempted	O
to	O
solve	O
this	O
for	O
a	O
campus	O
environment	O
using	O
caching	B-General_Concept
and	O
a	O
weak	B-General_Concept
consistency	I-General_Concept
model	I-General_Concept
to	O
achieve	O
local	O
access	O
to	O
remote	O
files	O
.	O
</s>
<s>
In	O
the	O
2000	O
's	O
,	O
global	B-Operating_System
file	I-Operating_System
systems	I-Operating_System
have	O
found	O
a	O
use	O
case	O
in	O
providing	O
hybrid	B-General_Concept
cloud	I-General_Concept
storage	I-General_Concept
,	O
that	O
combine	O
cloud	O
or	O
any	O
object	B-Application
storage	I-Application
,	O
versioning	O
and	O
local	O
caching	B-General_Concept
to	O
create	O
a	O
single	O
,	O
unified	O
,	O
globally	O
accessible	O
file	B-Application
system	I-Application
that	O
does	O
not	O
rely	O
on	O
redirection	O
to	O
a	O
storage	O
device	O
but	O
serves	O
files	O
from	O
the	O
local	O
cache	B-General_Concept
while	O
maintaining	O
the	O
single	O
file	B-Application
system	I-Application
and	O
all	O
meta	O
data	O
in	O
the	O
object	B-Application
storage	I-Application
.	O
</s>
<s>
As	O
described	O
in	O
Google	B-Application
's	I-Application
patents	O
,	O
advantages	O
of	O
these	O
global	B-Operating_System
file	I-Operating_System
systems	I-Operating_System
include	O
the	O
ability	O
to	O
scale	O
with	O
the	O
object	B-Application
storage	I-Application
,	O
use	O
snapshots	O
stored	O
in	O
the	O
object	B-Application
storage	I-Application
for	O
versioning	O
to	O
replace	O
backup	O
,	O
and	O
create	O
a	O
centrally	O
managed	O
consolidated	O
storage	O
repository	O
in	O
the	O
object	B-Application
storage	I-Application
.	O
</s>
<s>
When	O
it	O
comes	O
to	O
hybrid	O
file	B-Application
storage	I-Application
,	O
there	O
are	O
two	O
main	O
approaches	O
:	O
network	B-Application
attached	I-Application
storage	I-Application
(	O
NAS	B-Application
)	O
with	O
cloud	O
connectivity	O
and	O
global	B-Operating_System
file	I-Operating_System
system	I-Operating_System
(	O
GFS	O
)	O
.	O
</s>
<s>
NAS	B-Application
with	O
cloud	O
connectivity	O
is	O
typically	O
used	O
to	O
supplement	O
on-premises	O
storage	O
.	O
</s>
<s>
Public	O
clouds	O
may	O
be	O
combined	O
with	O
on-premises	O
NAS	B-Application
for	O
tasks	O
such	O
as	O
backup	O
,	O
tiering	O
,	O
or	O
disaster	O
recovery	O
.	O
</s>
<s>
On-premises	O
NAS	B-Application
is	O
sold	O
by	O
well-established	O
IT	O
vendors	O
including	O
Dell	O
,	O
IBM	O
,	O
NetApp	O
,	O
and	O
others	O
,	O
and	O
most	O
build	O
in	O
support	O
for	O
some	O
type	O
of	O
cloud	O
connectivity	O
.	O
</s>
<s>
A	O
Global	B-Operating_System
File	I-Operating_System
System	I-Operating_System
utilizes	O
a	O
fundamentally	O
different	O
architecture	O
.	O
</s>
<s>
In	O
these	O
solutions	O
,	O
cloud	O
storage	O
–	O
typically	O
object	B-Application
storage	I-Application
–	O
serves	O
as	O
the	O
core	O
storage	O
element	O
,	O
while	O
caching	B-General_Concept
devices	O
are	O
utilized	O
on-premises	O
to	O
provide	O
data	O
access	O
.	O
</s>
<s>
These	O
devices	O
can	O
be	O
physical	O
but	O
are	O
increasingly	O
available	O
as	O
virtual	O
solutions	O
that	O
can	O
be	O
deployed	O
in	O
a	O
hypervisor	B-Operating_System
.	O
</s>
<s>
The	O
use	O
of	O
caching	B-General_Concept
devices	O
reduces	O
the	O
amount	O
of	O
required	O
on-premises	O
storage	B-General_Concept
capacity	I-General_Concept
,	O
and	O
the	O
associated	O
capital	O
expense	O
.	O
</s>
<s>
Global	B-Operating_System
file	I-Operating_System
systems	I-Operating_System
are	O
better	O
suited	O
for	O
remote	O
collaboration	O
,	O
as	O
they	O
make	O
it	O
easier	O
to	O
manage	O
access	O
to	O
files	O
across	O
dispersed	O
geographic	O
areas	O
.	O
</s>
<s>
Notable	O
vendors	O
in	O
the	O
global	B-Operating_System
filesystem	I-Operating_System
area	O
include	O
:	O
</s>
