Tuesday, November 25, 2014

Checking Backed Up Data - The Lesson We can Learn from Bitcasa

There are plenty of reports about data loss and corruption from data stored with Bitcasa in the news.  Any time someone's data is lost it is unfortunate.  Whether the reports are accurate or not, they bring up a good point about data protection.  Backing up your data is just not enough.  Just as you would not add oil to a car without checking the dipstick to verify it is enough or not too much, backing up files without checking them is risky.  In most cases the data should and will be fine, but there is always a chance something bad can happen along the way.

If you have any data you are not willing to lose like photos, videos of events, trips or family, work product or tax documents, hopefully you are backing up your data somewhere.  Obviously there are many backup choices, a second partition on a disk drive, an external USB drive, a flash drive, and of course cloud storage.  Beyond the storage device, if not using cloud storage, then an offsite location needs to be a consideration.  Offsite storage is important because a theft, natural disaster, or fire can take out the device holding the original content as well as the backup devices if they are all stored in one location.

So how should people protect themselves?

When you have gone to the effort to make a backup, or use a cloud service to automatically backup your data, the job seems done, right?  The answer is not necessarily.  After backing up your data, regardless of the way you back it up, it is a good idea to spot check random files backed up.  How often you check the data should reflect how important the data is and how impactful it would be to lose the data.  For most people, once a quarter is sufficient and only a few files need to be checked at a time.  The ease of checking these files is dependent upon the type of data backed up.

How can the integrity of the data be checked?
If the files are backed up to a secondary partition, USB drive, or flash drive, test opening any common files like photos, documents, or videos from the backup location to verify the files are intact.  Files backed up to the cloud can also be regularly checked.  To check these files, log into your cloud account and browse through a few different dates of backed up data.  Open a few common files like photos, documents, or videos to verify the files are intact.  With a cloud backup service, there could be different versions of files to browse through.  If desired, open a document or file from two different backup dates, one before a change was made to the file, and one after the change to verify the file is being captured and stored in both states correctly.

What if a database is being backing up?
If you have database files, checking the files is more of a process.  If you have a test server running the same database applications as the live applications, upload the database files to the test server and verify the data is correct.  Without a test server, the process is a little longer.  The following steps can test a backed up database file in most situations:
  • Stop the services running the database.  
  • Change the name of the existing database file.
  • Restore the database file from a backup to the location of the original database.
  • Restart the database services and log into the application to verify the information in the database backup file is correct.
  • Stop the services running the database.
  • Remove the backup file.
  • Rename the local database file back to its original name.
  • Restart the services running the database.
  • Log into the application to verify the database is running correctly.

Backing up data is important, but it is also important to check these backups.  However you backup your data, it is important to check them to make sure the data is being backed up correctly, as expected, and that file corruption is not present.  If you have database files, the process is more complex, but the potential loss is also much higher.  Regardless of the data being backed up, verifying these files will be available if and when they are ever needed is an important part of the process of data protection.  The time spent checking backups will go a long way towards easing stress and ensuring your data is protected if something happens to the original versions of these files.

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