<s>
Scribe	B-Application
was	O
a	O
server	O
for	O
aggregating	O
log	B-Application
data	I-Application
streamed	O
in	O
real-time	O
from	O
many	O
servers	B-Application
.	O
</s>
<s>
It	O
was	O
designed	O
to	O
be	O
scalable	B-Architecture
,	O
extensible	O
without	O
client-side	O
modification	O
,	O
and	O
robust	O
to	O
failure	O
of	O
the	O
network	O
or	O
any	O
specific	O
machine	O
.	O
</s>
<s>
Scribe	B-Application
was	O
developed	O
at	O
Facebook	O
and	O
released	O
in	O
2008	O
as	O
open	B-Application
source	I-Application
.	O
</s>
<s>
Scribe	B-Application
servers	B-Application
are	O
arranged	O
in	O
a	O
directed	O
graph	O
,	O
with	O
each	O
server	O
knowing	O
only	O
about	O
the	O
next	O
server	O
in	O
the	O
graph	O
.	O
</s>
<s>
This	O
network	B-Architecture
topology	I-Architecture
allows	O
for	O
adding	O
extra	O
layers	O
of	O
fan-in	O
as	O
a	O
system	O
grows	O
,	O
and	O
batching	O
messages	O
before	O
sending	O
them	O
between	O
datacenters	O
,	O
without	O
having	O
any	O
code	O
that	O
explicitly	O
needs	O
to	O
understand	O
datacenter	O
topology	B-Architecture
,	O
only	O
a	O
simple	O
configuration	O
.	O
</s>
<s>
Scribe	B-Application
was	O
designed	O
to	O
consider	O
reliability	O
but	O
to	O
not	O
require	O
heavyweight	O
protocols	O
and	O
expansive	O
disk	O
usage	O
.	O
</s>
<s>
Scribe	B-Application
spools	O
data	O
to	O
disk	O
on	O
any	O
node	O
to	O
handle	O
intermittent	O
connectivity	O
node	O
failure	O
,	O
but	O
does	O
n't	O
sync	O
a	O
log	O
file	O
for	O
every	O
message	O
.	O
</s>
<s>
However	O
,	O
this	O
degree	O
of	O
reliability	O
is	O
often	O
suitable	O
for	O
most	O
Facebook	O
use	B-Architecture
cases	I-Architecture
.	O
</s>
