How many apps does it take to back up your data?
Trevor Pott counts the ways
Sysadmin blog What is the better approach to backups: a single service that can back up everything on your network or a collection of applications for backing up different items?
Over the course of my career I have been on both sides of this argument and I am still not convinced either is right. Now a pending network upgrade has forced me to scrap a recent backup plan and reopen the old debate.
The more the merrier
One of the simplest reasons to look towards multiple backup applications – or multiple instances of the same application – is restore speed.
I have had to do a few full-bore disaster recovery events: they aren't pretty and they aren't fun. The process is nerve-wracking for everyone. Will the backups work? Was anything lost? What was lost? How much will this cost?
As well as the human side of the equation there is the more pragmatic time-is-money maths. Our data centres are increasingly interdependent. Restoring data for one application doesn't mean you can use it; often you need to get many more applications up and running – or even all of them – before the critical bit everyone is waiting for will function.
Some backup providers grok this, others don't, but in my experience no single application is as fast as a restore from multiple points simultaneously.
How will I know?
The number of applications we use every day is growing. We have only to look at our own homes. We have moved from a PC with a handful of apps to everyone having their own mobile device each with its own unique app loadout.
How can one backup application be expected to know about all the applications in our data centres or all of the cloudy SaaS apps we are increasingly dependent upon?
A backup regime that can't back up all your data is kind of pointless, and I fear that it is increasingly unrealistic to expect any single application to do backups for every app in use.
One thing that single backup applications frequently lack is the ability to treat different classes of data with different priorities. Every backup application I have worked with for the past 10 years or so has had the ability to do backups with differing frequency depending on source. Few can do it based on data content; that still requires scripting.
I look for more: the ability to choose the backup medium (or destination) based on data source, content, document ownership and so on; automatic duplication of some categories of data to multiple destinations; and in some cases data is so mission critical that I require an unencrypted, un-deduplicated copy ready for immediate launch in a cold standby facility.
In practice, this has meant using multiple applications just to get the feature coverage I seek.
Trust me, I’m a provider
A large part of the argument for multiple backup applications revolves around trust. Using a single backup provider means trusting that application or its vendor to be there for you when you need them. I have seen all sorts of things go sideways during restores and it leaves me very leery of backup providers in general.
What happens if the backup manifest is corrupted? Does the application have a means to rebuild it? Do you know how to do it on your own and if not would the vendor help?
If you use an online provider as the backup destination how flexible would it be? If part of your disaster involves the loss of your high-bandwidth internet connection will the company freight you disks? Will it do it without charging you the GDP of Ghana?
A single backup provider has the potential to be a single point of failure. I have certainly been in the situation where the vendor refused to support an older version of its software. The backup software naturally went sideways during restore and the lack of support was infuriating.
What happens if the only guy in the company who knows how to make the thing work gets hit by a bus?
Similarly, I can't imagine trusting all of my backups to a single online provider. It is only where a single provider is providing both local software – or a local appliance – in combination with an online service that I could see a it moving past that single point of failure.
In this case, trust would depend entirely on reputation. How long has the provider been in business? Are backups core to its offering or just a transient sideline that it will throw overboard when it doesn't demonstrate year-on-year growth far exceeding analysts’ expectations?
Another consideration that pushes me towards multiple applications is centred on the trust we may or may not have in the sysadmins overseeing the process. Backup applications are complex and frequently difficult to use.
What happens if the only guy in the company who knows how to make the thing work gets hit by a bus? Are you certain that knowledge has been passed to others?
Multiple applications at least give the opportunity to make several individuals (or departments) responsible for backup applications. If you have a few people used to their own backup applications, they can usually put their heads together and figure out how a different one works.