Losing documents – cherished photos, or vital work – is tragic, costly, and wastes time. Combat the risk by designing a backup strategy.

One of the toughest situations that readers used to report to the Help desk at MacUser was data loss. It could be as commonplace as an application error that seems to have blown away a precious collection of photos or vital mailbox, or a dead startup disk. Only a couple of days ago, I was asked to help someone who has apparently had all their Time Machine backups blown away, bar the most recent.

Those that have recent complete backups expect a bit of pain and wasted time recovering, but sadly some admit to having no such fallback. If you cannot come up with a miraculous recovery plan, your documents will have gone to the great bit bucket in the sky, forever.

Unfortunately most advice and references on backup and archiving are aimed at larger networks, with greater needs, and more resources to throw at the problem.

For many of us it would be perfect if we could leave the matter to a system administrator, who would then schedule an overnight transfer of key data to removable media, perhaps. However we have to look after ourselves, can afford next to no time to solve the problems or implement the solution, and would prefer something that was cheap if not free.

The only rational way to approach this is to examine the risks, then address those risks that are most likely, and which would cost us most dearly. Like everything else, we must think real, coming up with real-world solutions, and using them properly. This means listing those events that are likely to lead to data loss, and devising strategies to deal with each.

Missing document

The most common cause of data loss is that you (or, as we always insist, someone else) accidentally trash your working copy of a vital document; variations include corruption or apparent loss of a photo library, mailbox, and the like. What you need is another copy of that document, which can be provided by a wide range of different solutions.

Among the most popular is Time Machine, which automatically makes hourly copies of almost all the files on designated volumes to another hard disk. This meets the requirement of making a recent copy of everything of significance readily to hand, provided that you can use Time Machine.

It is less appropriate for systems that are seldom back at base, and can run backups infrequently, although it will continue to make hidden backups to your internal hard disk even then. Time Machine can be run over a network, for instance to a Time Capsule or other networked storage, but that may not be as robust.

Disk crash

The next common scenario is that your startup (or other) hard disk crashes, or its contents are otherwise damaged, so that you lose all important documents stored on them. This does not necessarily render your Mac unusable: Mac Pros, for instance, can readily be switched to starting up from another internal drive.

But instead of needing ready access to just your working documents, you will now need to be able to restore all the essential contents of the dead disk, including extensions, applications, and your Home folder. Again Time Machine is a good solution, but if that is not feasible you could use a recent clone or mirror copy of the disk, perhaps created using Carbon Copy Cloner or SuperDuper!, augmented by more contemporary versions of working documents, mailboxes, and the like.

Dead Mac

A more serious calamity is the death of your whole Mac, such as when the logic board or power supply fails, requiring it to be sent away for repair, or replaced.

In this case, good solutions are similar to those for a dead disk, but a recent clone may prove less useful than Time Machine, as you may have to restore your files to a new or different Mac. You can of course accomplish this from a clone of your old Mac’s disk, running Migration Assistant to move documents and other components from the copy to your repaired or replaced Mac.

Similar solutions apply to the scenario that your Mac (most probably a laptop) is stolen or ‘misplaced’.

Disaster

So far we have assumed that you have been deprived of access only to your Mac or its disk storage. You must also consider making allowance for more serious situations, in which your office or home is affected. Natural disasters such as fire and flood are distressingly common, or you could be unable to access your office or home because you have become marooned somewhere else by the weather or travel disruption, or the premises are closed off because of a local disaster.

You may still be able to gain access to locally stored files – if you can afford it, a data recovery specialist may be able to extract the entire contents of a hard disk affected by flood or smoke damage – but you are better relying on off-site storage.

A relatively expensive but excellent solution can be to keep all important files on a hot-swappable RAID mirror store. At the end of each working day, the mirror is split by popping one of the drives, which is then taken off-site. A fresh drive is inserted in its place, which the RAID system then rebuilds into its mirror pair overnight.

Remote data storage is also becoming readily available in the form of cloud storage, most obviously Apple’s iCloud. As a vogue service, there is no shortage of providers vying to hold your files, and you should certainly not assume that iCloud is the only or best solution.

More traditional solutions, such as making weekly copies of all your working documents to a DVD or two and storing those in a document fire-safe in a friend’s flat on the other side of town, are cheap and surprisingly robust, provided that you remember to do it regularly.

Critical illness or death

A final scenario to contemplate is that you become seriously ill or die, and your nearest and dearest need to access vital files, such as your work in progress.

If you work with partners, ensure that they know where you keep records of all key user names and passwords, so that they have ready access to all your essential activities. They can only receive and deal with your incoming email if they can add your mail account (including its password) to their mailboxes.

If you need to encrypt or otherwise protect personal data, to comply with the Data Protection Act, they must also know how to access that. Although HMRC tries to be considerate when disaster strikes businesses, you will still incur hefty penalties if VAT and tax returns are not made promptly without agreeing leeway in advance.

Your own list of scenarios may be quite different, and your assessment of their risks will vary according to what you do. If you are a press photographer who periodically goes to remote and dangerous parts of the world, your needs will contrast with those of a freelance illustrator based in a placid rural location, or a family living in London.

You need to be hard-nosed about the quantity of data you need to back up, and feasibility of using online services such as the Cloud.

Whatever systems you decide to employ, you must check that they work by periodically retrieving files from them. There is nothing more embarrassing and costly than going to restore a system from its backup, only to discover that the backup is missing, blank, or unusable.

Tool: Time Machine

It is probably fair to say that before Apple built Time Machine into Leopard, most individual Mac users did not make regular or frequent backups, and very few had recent full backups that would enable disaster recovery. Bundling Time Machine into Leopard and subsequent releases of OS X has thus safeguarded a vast amount of data, across those millions of Mac users.

However Time Machine is not a complete solution, and simply clagging a large external drive onto your iMac and turning its hourly backups on does not guarantee that you will never lose data. Most obviously a local backup, no matter how extensive, does not protect from many common risks such as lightning strike, flood, and fire.

In some ways the zero cost and ready availability of Time Machine has induced users to ignore those other risks.

Reliance on Time Machine has also caused problems when backups have not included essential files, or those backups fail to work as expected. It is tempting to exclude files that change repeatedly, such as mailboxes, and very large files, such as video, databases, and PC virtual disks, from backing up, so that the backup drive does not fill up too rapidly.

This is almost always false economy for mailboxes, which are among the most vulnerable of data to damage. Very large files should be backed up separately if they are to be excluded from Time Machine, something that is easy to overlook.

If you use Time Machine, you should also periodically check the integrity of its backups by retrieving old documents from them. This is particularly important if you are using an unconventional backup location, such as on networked storage, or have tweaked or customised Time Machine in any way. You should also change backup drive early, before running out of space.

Tool: iCloud

The most attractive possible backup is off-site, even out of country, transparently accessible to all your authorised devices from anywhere in the world: the ‘cloud’.

In truth this is not as novel as it may seem, as FTP archives have been used for this purpose since the dawn of the Internet. What is new is that several major providers are competing to store your data in ways that are ever more convenient, and at this stage many are free, at least for the first few gigabytes.

Apple’s offering is iCloud, successor to the likes of iDisk and MobileMe, which is now well-integrated into Yosemite. Before it can compete with existing local and off-site backup techniques for Macs, you will need to rent additional storage space and maintain a very high bandwidth connection with Apple’s data centre.

However it is already proving valuable for sharing documents and data with and between iOS devices, for off-site backup of key documents, and online recovery for mobile Macs.

Before you can build iCloud into your backup and recovery scheme, you must ensure that wherever you are you can guarantee robust high-speed broadband connections. If your work takes you into more rural areas of Wales or Scotland, this could be a show-stopper.

Cloud reliability is a thorny issue that providers are perhaps not always completely honest about: Microsoft’s much-vaunted Azure cloud service suffered 241 outages in 2014, leaving users stranded for up to nearly 43 hours in total, and back in March 2015 iCloud was down for 12 hours as a result of an ‘internal DNS error’.

Disaster situations are those in which maintaining good server connections may be most challenging, particularly where those connections are vulnerable at so many single points of failure. Handling sensitive data, regulated under the Data Protection Act, is also controversial and needs caution: see this article for details.

Updated from the original, which was first published in MacUser volume 28 issue 08, 2012.