<s>
In	O
database	B-Application
systems	I-Application
,	O
durability	B-General_Concept
is	O
the	O
ACID	O
property	O
which	O
guarantees	O
that	O
transactions	O
that	O
have	O
committed	O
will	O
survive	O
permanently	O
.	O
</s>
<s>
Durability	B-General_Concept
can	O
be	O
achieved	O
by	O
flushing	O
the	O
transaction	B-General_Concept
's	O
log	O
records	O
to	O
non-volatile	B-General_Concept
storage	I-General_Concept
before	O
acknowledging	O
commitment	O
.	O
</s>
<s>
In	O
distributed	B-General_Concept
transactions	I-General_Concept
,	O
all	O
participating	O
servers	O
must	O
coordinate	O
before	O
commit	O
can	O
be	O
acknowledged	O
.	O
</s>
<s>
This	O
is	O
usually	O
done	O
by	O
a	O
two-phase	B-General_Concept
commit	I-General_Concept
protocol	I-General_Concept
.	O
</s>
<s>
Many	O
DBMSs	O
implement	O
durability	B-General_Concept
by	O
writing	O
transactions	O
into	O
a	O
transaction	B-General_Concept
log	I-General_Concept
that	O
can	O
be	O
reprocessed	O
to	O
recreate	O
the	O
system	O
state	O
right	O
before	O
any	O
later	O
failure	O
.	O
</s>
<s>
A	O
transaction	B-General_Concept
is	O
deemed	O
committed	O
only	O
after	O
it	O
is	O
entered	O
in	O
the	O
log	O
.	O
</s>
