When we mention backups, everybody will think, “hey, my data is safe anyway, isn’t it? I mean this is a reputable ISP, sure they have enterprise disks and RAID, and whatnot? Or don’t they?!”.
There are two important NBs when it comes to backing up your data, be it on a Virtual Private Server (VPS) or on dedicated servers:
- Don’t assume anyone but you is going to back up your data.
- Don’t assume that even if your ISP backs up your data that you shouldn’t as well.
By default, it is safe to assume that your provider does not back up your data. Typically, explicit backups will cost you some additional money, and even then you are well advised to ask your ISP what they are backing up, and how, how often they do they it, and where the data is being kept.
A couple of bad backup solutions:
- different disk (or, worse even, partition) on the same machine;
- some external drive, like a USB disk;
A couple of decent/workable backup solutions:
- standby server in the same DC;
- ftp space on some other machine in the same DC;
- making sure disks are RAID (this is not, however, a real backup strategy, it just helps to gain some redundancy and should be treated more like a complementing measure; no ISP should, unless explicitly asked to, offer you a setup without RAID; a disk failure in a RAID setup at least allows online recovery in hot swap environments);
A good backup solution:
- generation driven backup strategy on a server or backup system (such as IBM’s TSM which can backup to SAN and tape, or bacula, which is free of charge and can perform full/differential/incremental backups for example) in a different DC;
Any ISP employing one of the bad solutions means that you should explicitly look for a service that allows you to at least back up your data somewhere else as well, in a different data centre. You should also consider this when your ISP can only offer a backup solution that can be considered workable at best. If your ISP, however, can prove that they are using an enterprise solution to back up your data, then you can assume that your data is safe – nevertheless you should back up your data as well. At least make dumps and tgz’s of your most important data, download it, and store it safely away, burn it to CD/DVDs, etc. Be prepared for the worst case, backups can go corrupt, you might accidentally delete all instances of one file desperately needed, etc.
Backing up is only half the story – data backed up is pretty, but you also need to be able to restore it. Make sure to test your backup/restore strategy. Back up data, restore it, see if it works. Repeat this in regular intervals, and repeat it whenever you do major changes to your application or when you need to document milestones, etc. Ask yourself, how much is your data worth to you? What if you lose everything? When it comes to your data, it comes to your online presence, your enterprise and company: Don’t assume. Make sure.