Despite the availability of newer alternatives such as hard disks, solid state storage, optical storage and remote services, tape is still the most commonly used medium for backing up and archiving corporate data. One reason for this prevalence is longevity of the technology. Magnetic tapes have been around much longer than any of the alternatives. The other main reason is price. Tape has always been less expensive than competing mediums, although this gap is now gradually closing.
There are, of course, downsides. Tapes can and do corrupt. Another problem is the time it takes to restore data from a tape. Therefore it pays to try to prevent problems by looking after the data on tape-based backup systems, with a simple maintenance regime. Here are four proven tips to help keep your archive working optimally.
Assess the health of your tape archive
If you drive a car you probably rely on your spare wheel. You assume that it is in good condition and capable of being used in the place of a flat tyre. Many IT managers assume the same about their tape archive. Backups are made and the tapes are put in a safe place, ready for the day when data may need to be restored. However, few bother to check the condition of the tapes.
There's a good chance the tapes you are looking after have been with the company longer than you. After all, tape has a life expectancy of 10 to 20 years in perfect conditions. The only problem is that few tapes are stored under “perfect” conditions and all modern storage media deteriorate due to external causes.
To avoid discovering damaged tapes just at the time when you are trying to restore critical data, it is paramount to periodically test the health of your tape archive by assessing the readability of sample tapes. What’s written to a tape could be garbage hence the need to validate. You should also check the availability and working condition of your tape solution, and your IT department's ability to work with legacy tape formats. If you lack the legacy knowledge or the time to carry out such tests, an external service provider can reduce the burden by conducting the review for you.
If you do already regularly test your tape archive, keep in mind that not every write error is recognised by the writing device. Always check your sample media after writing to it and always confirm the results by using a different device to read the media.
Upgrade old tape formats
As there are no hard-and-fast rules regarding tape end of life, organisations should put in place their own policies defining the expected tape lifespan. Policies may be based on a variety of factors including age of the tape, the number of times it is written to, or the read/write error rate. The important thing is to ensure consistent treatment of media and retirement of tapes at the most appropriate time.
In addition to policy-based reasons, companies may have suddenly find themselves facing an ad hoc requirement to upgrade the tape archive. Reasons for this include company mergers or de-mergers, data centre relocation, compliance, risk management, a back up technology refresh or the need to realise savings on physical storage costs. The discovery of damaged or corrupt tapes often plays a role in these decisions.
Whatever the driver for an upgrade, the three most common responses are:
- copying to a similar medium (otherwise known as a “refresh”);
- copying to a different medium (migration); or
- copying to a different storage model such as archiving in a public or private cloud solution.
IT departments should remain vigilant about monitoring the ageing of tapes and as retirement time draws near, take the opportunity to consider what storage model best suits the needs of the business. Rather than automatically carrying out a refresh, you may find it makes better financial sense to switch to a new model.
Changing the backup agent also means keeping the legacy backup server with all the catalogues so you have the index of the tapes to refer to. The cost of maintaining a legacy could be substantial $100K per year. An emerging trend is to use external providers for ad hoc tape restores on demand services which then negates the need to maintain legacy equipment. This is a big shift in thinking but could result in substantial archiving savings.
Migration to a new tape storage solution requires management
Tape migration is a series of steps, progressing from tape audit and media consolidation, to extraction, duplication and conversion. Many migrations involve a logistics challenge as tapes need to be transported to and from secured premises, so a strict chain of custody and data security protocols is a requirement if a tape leaves your premises. You should also consider the secured return of media or optional safe data erasure.
Once again, it's a good idea to have the services of a recognised data recovery specialist on hand in case you discover damaged or unreadable tapes. Look for a specialist with credentials and experience in the following areas:
- ability to support multiple tape types of different ages;
- support for current backup solutions;
- data recovery capabilities;
- secured logistics, and secured and monitored premises;
- project management skills;
- delivery of services according to a contractual framework;
- information lifecycle management capabilities
Data archiving is an ongoing process
Data archiving requires ownership and regular planning and review. Never assume data is accessible when left untouched because, as noted, all media deteriorate. If data is stored on site, recognise that not all IT departments can create the perfect conditions for long term storage. If data is stored off site, you not only need to assess the health of your media, but should also test the speed of data access.
With just a few routine maintenance tasks – regular health checks, upgrades when necessary, careful migration and an understanding of the need for ongoing management – the inevitable problems of tape corruption, wear and tear can be managed, minimising any risk of data loss.
Adrian Briscoe is the general manager Asia Pacfic of Kroll Ontrack.