<s>
Moose	B-Application
File	I-Application
System	I-Application
(	O
MooseFS	B-Application
)	O
is	O
an	O
open-source	B-Application
,	O
POSIX-compliant	O
distributed	B-Protocol
file	I-Protocol
system	I-Protocol
developed	O
by	O
Core	O
Technology	O
.	O
</s>
<s>
MooseFS	B-Application
aims	O
to	O
be	O
fault-tolerant	B-General_Concept
,	O
highly	O
available	O
,	O
highly	O
performing	O
,	O
scalable	O
general-purpose	O
network	O
distributed	B-Protocol
file	I-Protocol
system	I-Protocol
for	O
data	B-Operating_System
centers	I-Operating_System
.	O
</s>
<s>
Initially	O
proprietary	B-Application
software	I-Application
,	O
it	O
was	O
released	O
to	O
the	O
public	O
as	O
open	B-Application
source	I-Application
on	O
May	O
30	O
,	O
2008	O
.	O
</s>
<s>
Currently	O
two	O
editions	O
of	O
MooseFS	B-Application
are	O
available	O
:	O
</s>
<s>
MooseFS	B-Application
-	O
released	O
under	O
GPLv2	O
license	O
,	O
</s>
<s>
MooseFS	B-Application
Professional	O
Edition	O
(	O
MooseFS	B-Application
Pro	O
)	O
-	O
release	O
under	O
proprietary	B-Application
license	I-Application
in	O
binary	O
packages	O
form	O
.	O
</s>
<s>
The	O
MooseFS	B-Application
follows	O
similar	O
design	O
principles	O
as	O
Fossil	B-Application
(	O
file	O
system	O
)	O
,	O
Google	B-Application
File	I-Application
System	I-Application
,	O
Lustre	B-Application
or	O
Ceph	O
.	O
</s>
<s>
The	O
current	O
version	O
of	O
MooseFS	B-Application
does	O
support	O
multiple	O
metadata	O
servers	O
and	O
automatic	O
failover	B-General_Concept
.	O
</s>
<s>
The	O
Metadata	O
server	O
is	O
a	O
user-space	O
daemon	B-Operating_System
;	O
the	O
metadata	O
is	O
kept	O
in	O
memory	O
and	O
lazily	O
stored	O
on	O
local	O
disk	O
.	O
</s>
<s>
The	O
Chunk	O
server	O
is	O
also	O
a	O
user-space	O
daemon	B-Operating_System
that	O
relies	O
on	O
the	O
underlying	O
local	O
file	O
system	O
to	O
manage	O
the	O
actual	O
storage	O
.	O
</s>
<s>
MooseFS	B-Application
clients	O
mount	O
the	O
file	O
system	O
into	O
user-space	O
via	O
FUSE	B-Application
.	O
</s>
<s>
To	O
achieve	O
high	O
reliability	O
and	O
performance	O
MooseFS	B-Application
offers	O
the	O
following	O
features	O
:	O
</s>
<s>
Fault-tolerance	B-General_Concept
—	O
MooseFS	B-Application
uses	O
replication	B-Architecture
,	O
data	O
can	O
be	O
replicated	O
across	O
chunkservers	O
,	O
the	O
replication	B-Architecture
ratio	O
(	O
N	O
)	O
is	O
set	O
per	O
file/directory	O
.	O
</s>
<s>
If	O
(	O
N-1	O
)	O
replicas	B-Architecture
fail	O
the	O
data	O
will	O
still	O
be	O
available	O
.	O
</s>
<s>
At	O
the	O
moment	O
MooseFS	B-Application
does	O
not	O
offer	O
any	O
other	O
technique	O
for	O
fault-tolerance	B-General_Concept
.	O
</s>
<s>
Fault-tolerance	B-General_Concept
for	O
very	O
big	O
files	O
thus	O
requires	O
vast	O
amount	O
of	O
space	O
-	O
N*filesize	O
instead	O
of	O
filesize+( N*stripesize	O
)	O
as	O
would	O
be	O
the	O
case	O
for	O
RAID	O
4	O
,	O
RAID	O
5	O
or	O
RAID	O
6	O
.	O
</s>
<s>
Version	O
4.x	O
PRO	O
of	O
MooseFS	B-Application
implements	O
8+n	O
Erasure	O
Coding	O
.	O
</s>
<s>
Striping	B-General_Concept
—	O
Large	O
files	O
are	O
divided	O
into	O
chunks	O
(	O
up	O
to	O
64	O
megabytes	O
)	O
that	O
might	O
be	O
stored	O
on	O
different	O
chunk	O
servers	O
in	O
order	O
to	O
achieve	O
higher	O
aggregate	O
bandwidth	O
.	O
</s>
<s>
Load	B-Application
balancing	I-Application
—	O
MooseFS	B-Application
attempts	O
to	O
use	O
storage	O
resources	O
equally	O
,	O
the	O
current	O
algorithm	O
seems	O
to	O
take	O
into	O
account	O
only	O
the	O
consumed	O
space	O
.	O
</s>
<s>
Security	O
—	O
Apart	O
from	O
classical	O
POSIX	O
file	O
permissions	O
,	O
since	O
the	O
1.6	O
release	O
MooseFS	B-Application
offers	O
a	O
simple	O
,	O
NFS-like	O
,	O
authentication/authorization	O
.	O
</s>
<s>
Coherent	B-Application
snapshots	I-Application
—	O
Quick	O
,	O
low-overhead	O
snapshots	B-Application
.	O
</s>
<s>
Similarly	O
to	O
other	O
cluster-based	O
file	O
systems	O
MooseFS	B-Application
uses	O
commodity	B-Device
hardware	I-Device
running	O
a	O
POSIX	O
compliant	O
operating	O
system	O
.	O
</s>
<s>
TCP/IP	B-Protocol
is	O
used	O
as	O
the	O
interconnect	O
.	O
</s>
