<s>
A	O
very	B-General_Concept
large	I-General_Concept
database	I-General_Concept
,	O
(	O
originally	O
written	O
very	O
large	O
data	O
base	O
)	O
or	O
VLDB	O
,	O
is	O
a	O
database	O
that	O
contains	O
a	O
very	O
large	O
amount	O
of	O
data	O
,	O
so	O
much	O
that	O
it	O
can	O
require	O
specialized	O
architectural	O
,	O
management	O
,	O
processing	O
and	O
maintenance	O
methodologies	O
.	O
</s>
<s>
Early	O
metrics	O
were	O
the	O
size	O
of	O
the	O
database	O
in	O
a	O
canonical	O
form	O
via	O
database	B-Application
normalization	I-Application
or	O
the	O
time	O
for	O
a	O
full	O
database	O
operation	O
like	O
a	O
backup	B-Protocol
.	O
</s>
<s>
This	O
absolute	O
amount	O
of	O
data	O
has	O
varied	O
over	O
time	O
as	O
computer	O
processing	O
,	O
storage	O
and	O
backup	B-Protocol
methods	O
have	O
become	O
better	O
able	O
to	O
handle	O
larger	O
amounts	O
of	O
data	O
.	O
</s>
<s>
The	O
complexities	O
of	O
managing	O
a	O
VLDB	O
can	O
increase	O
exponentially	O
for	O
the	O
database	B-General_Concept
administrator	I-General_Concept
as	O
database	O
size	O
increases	O
.	O
</s>
<s>
To	O
overcome	O
these	O
issues	O
techniques	O
such	O
as	O
clustering	B-Architecture
,	O
cloned/replicated/standby	O
databases	O
,	O
file-snapshots	O
,	O
storage	O
snapshots	O
or	O
a	O
backup	B-Protocol
manager	O
may	O
help	O
achieve	O
the	O
RTO	O
and	O
availability	O
,	O
although	O
individual	O
methods	O
may	O
have	O
limitations	O
,	O
caveats	O
,	O
license	O
,	O
and	O
infrastructure	O
requirements	O
while	O
some	O
may	O
risk	O
data	O
loss	O
and	O
not	O
meet	O
the	O
recovery	O
point	O
objective	O
(	O
RPO	O
)	O
.	O
</s>
<s>
Best	O
practice	O
is	O
for	O
backup	B-Protocol
and	I-Protocol
recovery	I-Protocol
to	O
be	O
architectured	O
in	O
terms	O
of	O
the	O
overall	O
availability	O
and	O
business	O
continuity	O
solution	O
.	O
</s>
<s>
Some	O
accesses	O
will	O
simply	O
have	O
more	O
data	O
to	O
process	O
(	O
scan	O
)	O
which	O
will	O
take	O
proportionally	O
longer	O
(	O
linear	O
time	O
)	O
;	O
while	O
the	O
indexes	B-Data_Structure
used	O
to	O
access	O
data	O
may	O
grow	O
slightly	O
in	O
height	O
requiring	O
perhaps	O
an	O
extra	O
storage	O
access	O
to	O
reach	O
the	O
data	O
(	O
sub-linear	O
time	O
)	O
.	O
</s>
<s>
Other	O
effects	O
can	O
be	O
caching	B-General_Concept
becoming	O
less	O
efficient	O
because	O
proportionally	O
less	O
data	O
can	O
be	O
cached	O
and	O
while	O
some	O
indexes	B-Data_Structure
such	O
as	O
the	O
B+	O
automatically	O
sustain	O
well	O
with	O
growth	O
others	O
such	O
as	O
a	O
hash	B-Algorithm
table	I-Algorithm
may	O
need	O
to	O
be	O
rebuilt	O
.	O
</s>
<s>
Should	O
an	O
increase	O
in	O
database	O
size	O
cause	O
the	O
number	O
of	O
accessors	O
of	O
the	O
database	O
to	O
increase	O
then	O
more	O
server	O
and	O
network	O
resources	O
may	O
be	O
consumed	O
,	O
and	O
the	O
risk	O
of	O
contention	B-General_Concept
will	O
increase	O
.	O
</s>
<s>
Some	O
solutions	O
to	O
regaining	O
performance	O
include	O
partitioning	B-General_Concept
,	O
clustering	B-Architecture
,	O
possibly	O
with	O
sharding	B-General_Concept
,	O
or	O
use	O
of	O
a	O
database	B-Device
machine	I-Device
.	O
</s>
<s>
Partitioning	B-General_Concept
may	O
be	O
able	O
assist	O
the	O
performance	O
of	O
bulk	O
operations	O
on	O
a	O
VLDB	O
including	O
backup	O
and	O
recovery.	O
,	O
bulk	O
movements	O
due	O
to	O
information	B-Protocol
lifecycle	I-Protocol
management	I-Protocol
(	O
ILM	O
)	O
,	O
reducing	O
contention	B-General_Concept
as	O
well	O
as	O
allowing	O
optimization	O
of	O
some	O
query	O
processing	O
.	O
</s>
<s>
In	O
order	O
to	O
satisfy	O
needs	O
of	O
a	O
VLDB	O
the	O
database	O
storage	O
needs	O
to	O
have	O
low	O
access	O
latency	O
and	O
contention	B-General_Concept
,	O
high	O
throughput	O
,	O
and	O
high	O
availability	O
.	O
</s>
<s>
VLDB	O
is	O
not	O
the	O
same	O
as	O
big	B-Application
data	I-Application
,	O
however	O
the	O
storage	O
aspect	O
of	O
big	B-Application
data	I-Application
may	O
involve	O
a	O
VLDB	O
database	O
.	O
</s>
<s>
That	O
said	O
some	O
of	O
the	O
storage	O
solutions	O
supporting	O
big	B-Application
data	I-Application
were	O
designed	O
from	O
the	O
start	O
to	O
support	O
large	O
volumes	O
of	O
data	O
,	O
so	O
database	B-General_Concept
administrators	I-General_Concept
may	O
not	O
encounter	O
VLDB	O
issues	O
that	O
older	O
versions	O
of	O
traditional	O
RDBMS	O
's	O
might	O
encounter	O
.	O
</s>
