TCO
Reinvented
Copyright IBM Corporation 2009
18
Power and cooling savings
High density drives are also
more efficient to operate. The XIV system’s ability to meet
the same needs with fewer drives and through greater per drive efficiency creates
corresponding cost savings in power and cooling.
To determine the savings in power and cooling from replacing your Medium Density Fast
Rotation (MDFR) drives with Very High Density Slower Rotation (VHDSR) drives, use
values relevant to your storage operation in the formulas below.
►
To compare RAID-1 drives to XIV's VHDSR drives, use the following formula:
% Savings in Power & Cooling = {1 – 0.75 (Your MDFR Drive
Size) / (the XIV system VHDSR Drive Size)} * 100
For example:
Assuming you are comparing your existing 146 GB drives to XIV's
1 TB (1000 GB) drives, the power and cooling savings are calculated as follows:
% Savings in Power & Cooling = {1–0.75(146)/
(1000)} * 100
=
=
8
8
9
9
%
%
►
To compare RAID-5 drives to XIV's VHDSR drives, use the following formula:
% Savings in Power & Cooling = {1 – 0.75 [0.8(Your MDFR Drive
Size)] / [0.5(the XIV system VHDSR Drive Size)]} * 100
For example
: Assuming you are comparing your existing 300 GB drives in a
RAID-5 configuration to XIV's 1 TB (1000 GB) drives, the power and cooling
savings are calculated as follows:
% Savings in Power & Cooling = {1 – 0.75 * [0.8 * (300)] /
[0.5 * 1000]} * 100
=
=
5
5
2
2
%
%
►
To compare 450 GB RAID-5 drives to XIV's 1 TB (1000 GB) drives, use the
following formula:
% Savings in Power & Cooling = {1 – 0.75 * [0.8 * (450)] /
[0.5 * 1000]} * 100 =
4
4
6
6
%
%
As noted, to make similar calculations for a RAID-6 (4+2) array, simply replace the 0.8
coefficient in the formulas by 0.75.
Use your own figures to calculate your potential savings. Apply the percentage that you
calculate to your data center's current utility bills to truly grasp the significance that these
savings can have on your annual budget. The results may astound you.
We invite you to contact your IBM/XIV representative to learn more.
