<s>
In	O
computing	O
,	O
a	O
virtual	B-Application
file	I-Application
server	I-Application
is	O
a	O
system	O
consisting	O
of	O
one	O
or	O
more	O
virtualized	B-Application
devices	O
that	O
store	O
computer	O
files	O
such	O
as	O
documents	O
,	O
sound	O
files	O
,	O
photographs	O
,	O
movies	O
,	O
images	O
,	O
or	O
databases	O
.	O
</s>
<s>
The	O
server	B-Application
can	O
be	O
accessed	O
by	O
workstations	B-Device
or	O
application	O
servers	O
through	O
the	O
Virtual	B-Application
Fileserver	I-Application
Network	I-Application
(	O
VFN	O
)	O
.	O
</s>
<s>
The	O
term	O
"	O
server	B-Application
"	O
highlights	O
the	O
role	O
of	O
the	O
virtual	O
machine	O
in	O
the	O
client-server	O
scheme	O
,	O
where	O
the	O
clients	O
are	O
the	O
applications	O
accessing	O
the	O
storage	O
.	O
</s>
<s>
The	O
file	B-Application
server	I-Application
usually	O
does	O
not	O
run	O
application	O
programs	O
on	O
behalf	O
of	O
the	O
clients	O
.	O
</s>
<s>
With	O
a	O
storage	O
area	O
network	O
(	O
SAN	O
)	O
,	O
the	O
server(s )	O
act	O
purely	O
as	O
virtual	O
storage	O
devices	O
,	O
with	O
a	O
client	O
maintaining	O
the	O
file	B-Application
system	I-Application
.	O
</s>
<s>
With	O
network-attached	B-Application
storage	I-Application
(	O
NAS	B-Application
)	O
,	O
the	O
server(s )	O
manage	O
the	O
file	B-Application
system	I-Application
.	O
</s>
<s>
Both	O
SAN	O
and	O
NAS	B-Application
servers	O
may	O
be	O
virtualized	B-Application
,	O
so	O
the	O
users	O
do	O
not	O
have	O
to	O
know	O
which	O
physical	O
devices	O
are	O
hosting	O
the	O
files	O
.	O
</s>
<s>
A	O
virtual	B-Application
file	I-Application
server	I-Application
typically	O
combines	O
the	O
security	O
of	O
virtual	B-Application
private	I-Application
networks	I-Application
(	O
VPN	B-Application
)	O
with	O
file	B-Application
synchronization	I-Application
,	O
distribution	O
and	O
sharing	O
services	O
of	O
network	B-Protocol
file	I-Protocol
servers	I-Protocol
.	O
</s>
<s>
Various	O
companies	O
offer	O
software	O
for	O
use	O
by	O
an	O
organization	O
in	O
managing	O
virtual	B-Application
file	I-Application
servers	I-Application
.	O
</s>
<s>
Some	O
companies	O
offer	O
virtual	B-Application
file	I-Application
servers	I-Application
as	O
a	O
service	O
to	O
organizations	O
that	O
prefer	O
to	O
outsource	O
server	B-Application
operations	O
,	O
with	O
the	O
servers	O
residing	O
in	O
the	O
"	O
cloud	B-Architecture
"	O
.	O
</s>
