Fortuna Power Systems Ltd – June 2007

GREEN DATA STORAGE

Written by

Ray Quattromini

Fortuna Power Systems Ltd Units B, E & F, Brickells Business Court Oakley Lane, Oakley Basingstoke Hampshire RG23 7JU

Tel: 01256 782030 E-mail: [email protected]

June 2007

Copyright Fortuna Power Systems Ltd 2007 This document may not be distributed or copied without the permission of the author. Fortuna Power Systems Ltd – June 2007

Green Data Storage

We all know that the our data storage requirements are doubling every 18 months and whilst disk capacities are also on the increase our appetite for faster, bigger storage arrays are increasingly growing to keep up with business needs. These storage arrays consume vast amounts of power; require cooling, maintenance and constant management. The need for Green Data Storage is greater now than it has ever been. With increasing electricity costs, the continual threat of power outages and global warming predictions, the whole area of data centre storage management needs to be addressed.

For example a 300GB 15k SAS disk drive uses 17.5 watts operating and a 750GB SATA-II drive uses 12 watts operating.

If we have a requirement for new 10TB storage array lets look at our storage options.

High Performance 300GB 15k rpm SAS Storage Array Therefore a 10TB storage array requires 34 disk drives consumes 595 watts per hour plus 150w for the RAID controller, PSU, fans etc

This equates to: • 17,880 watts or 61,012 BTU’s per day • 6,526,200 watts or 22,269,352 BTU’s per year • Running costs per annum £261 @ 0.04p per kilowatt hour excluding additional cooling costs

Lower Performance 750GB 7.2k rpm SATA-II Storage Array Therefore a 10TB storage array requires 14 disk drives consumes 168 watts per hour plus 150w for the RAID controller, PSU, fans etc

This equates to: • 7,632 watts or 26,042 BTU’s per day • 2,785,680 watts or 9,505,575 BTU’s per year • Running costs per annum £111 @ 0.04p per kilowatt hour excluding additional cooling costs

In order to reduce our carbon footprint we need to look at our whole data storage management infrastructure. It is a well known fact that 80% of our data is not accessed after 90 days. This data is backed up everyday to a set of tapes and kept for a specified period. This is a very in-efficient way of managing data!

Some storage array manufacturers are trying to conserve energy by power cycling the disk drives to save energy. Whilst in principle this sounds like a good idea in practise it decreases the reliability of the disk drives. If you run a disk drive 7x24 it should not be powered on/off more than 250 times per year otherwise you are exceeding the disk drive vendors operating specifications.

The Green Data Storage Alternative

What is required is a method of moving this in frequently accessed data to a more efficient Green alternative. Our primary choice is and our reasons for this are as follows:

• Better utilisation of available resources • Decreased backup window • Very low total cost of ownership • Very long archive life >50 years • Very power efficient • Increasing media capacities • Easy to store and duplicate • Business legislation and data compliance • Greatly enhances your disaster recovery SLA

Copyright Fortuna Power Systems Ltd 2007 This document may not be distributed or copied without the permission of the author. Fortuna Power Systems Ltd – June 2007

Example

10.5TB Blu-ray jukebox

A Blu-ray jukebox with four Blu-ray drives and 210 media slots consumes 140 watts per hour.

This equates to: • 3,360 watts or 11,465 BTU’s per day • 1,226,400 watts or 4,184,844 BTU’s per year • Running costs per annum £49 @ 0.04p per kilowatt hour no additional cooling is required

If we move 80% of our in-active data to a nearline optical jukebox our original requirement of a 10TB storage array now becomes 2TB and this is all that is needed to be backed up, therefore saving wear n tear on our robotic , less tapes and above a greatly reduced backup window while greatly reducing your recovery time in the event of a disaster. As our data is secured on an optical platter it does not need backing up and if you required you can create a 2 nd copy and keep this off-site for regulatory requirements.

Therefore a nearline optical archive with an access time to data of 20 seconds consumes 81% less power than a high performance SAS storage array and 56% less power using SATA. The other positive is that as higher capacity media becomes available your jukebox capacity also increases. At present Blu-ray media has a 50GB capacity and is scheduled over the next 2 years to increase to 200GB, therefore your jukebox would be able to scale to 42TB’s and still be capable of reading your archive data.

When considering a tiered archive solution for 10 years the storage devices will after 3-5 years need to be refreshed and in most instances storage arrays will be replaced by something faster with a higher capacity, the cost of disposing of this equipment will also increase over time. Conversely if you install an optical jukebox you might need to replace the original optical drives with the latest generation and retain the jukebox containing your archived data.

The Blu-ray is 120mm in diameter, the same as CD and DVD. This industry standard format size has been around for more than 25 years and is likely to remain the optical format size for many years to come as it is entrenched as a global media interchange format in both the home and the office and therefore devices should be capable of reading the data for a very long time.

What about tape? Tape has been around for nearly 60 years in various formats and types. Whilst tape is an ideal backup medium due to its large capacity ( LTO-4 800GB native) and fast transfer rate (LTO-4 120MB/s) it is not recommended as a long term archive media or as a nearline device. Our reasons for this are as follows:

• Tapes can only be read sequentially therefore it could take >54 seconds (LTO-4) to find the desired file, providing the tape is in the drive, whereas optical discs are random access. • Tapes are written using two contact surfaces e.g. the tape head and media. Whereas the laser does touch the surface of the disc. • The tape layers are in contact with each other which mean they will require periodic spooling to maintain data integrity. Optical discs data is written as a series of peaks and troughs over the discs surface. • They need to be stored in the right conditions to maintain data integrity. Optical discs are coated with a protective coating to prevent scratching, fading etc. • Tapes cannot be easily read on a desktop machine. Optical readers are very common.

Summary To summarise when considering a Greener Data Storage alternative, many things need to be taken into consideration such as speed of data access, data growth, power consumption, cooling, reliability, backup, DR etc.

Our business is based around supplying compliant tiered data storage hardware solutions allied to archiving software that meet today’s legislation regarding data retention and deletion requirements with scope and growth for future business changes.

If you want to know more about the solutions we can provide please call us on 01256 782030 or E-mail: [email protected].

Copyright Fortuna Power Systems Ltd 2007 This document may not be distributed or copied without the permission of the author.