Tuesday, 9 February 2010

Make Backups on External Hard Disks

Filed under: Hardware & Gadgets — Jan Goyvaerts @ 19:43

In my previous post I discussed how to organize data between an SSD and HDD. Though that implies two drives inside your PC, or two sets of drives if one SSD and one HDD don’t offer enough space, a proper data management plan for a workstation requires four drives. The internal SSD and HDD I discussed yesterday, an external backup disk I mentioned briefly, and the remote backup.

Hard disks have come down in price so much that it’s cheaper to back up data to hard disks than to optical media. It’s also much more convenient to organize everything on a big hard disk than to sift through piles of optical disks that may or may not still be readable. The back up hard disk gets used every day, so if it fails you know you need a new one right now. The only thing I still burn to DVD are operating system images that need to be bootable.

The backup drive should be an exteral HDD or an interal model that slides in and out of a SATA bay. I like to use a USB model to back up files because I can connect that to my laptop in case my desktop PC kicks the bucket.

It’s important that the backup drive is removed from the PC after you’ve made the backup. If your PC gets fried by lighting, fire, or superheated coffee, you don’t want your backup to die with the original. Put the backup in a different room, or take it home and put it under your pillow. You don’t want the backup to be stolen along with your PC.

The 4th hard disk is the off-site backup. The purpose of the off-site backup is to safeguard against total disaster, such as the building with your PC and your backup disk going up in smoke. The idea is to always have at least one backup that is not physically near the original data. So the external hard disk with your daily backup doesn’t count, because it’s connected to your PC while you’re making the backup. Having two external disks would work if you rotate them and one of them is always in a differrent building than your PC.

For my own off-site backup I installed a NAS (network attached storage device) on a relative’s home network. It’s actually off-continent. Being an expat in a country where immigration rules change with the season, I want a backup that protects against political risk. Not that I’ve ever had or expect any problems. Risk is irrelevant when storage is 10 cents per gigabyte.

Every day I backup up new files to the NAS via FTP. I don’t transfer operating system images, virtual machine images, and files that I’ll be deleting within the week anyway. That would all take too long on my ADSL line with 512K upload. Having to reinstall Windows is not the end of the world. I’ll likely need a new PC anyway if I ever have to recover using the off-site backup.

I prefer to maintain my own NAS rather than use an online service. If I ever need the off-site backup, it’s going to be because of a catastrophe like my house going up in smoke with computers and backups in it. Having to download a few hundred gigabytes of backup files would simply take too long. It’s faster and cheaper to have my relatives clone the backup disk using the empty second drive bay in the NAS and mail the clone by courier.


  1. Thanks for the great advice, I think I need to invest in some offsite hard drives :)

    Comment by Ben — Wednesday, 10 February 2010 @ 0:13

  2. Could you explain how you transfer to your relative’s NAS via ftp? How do you get the IP address? My relatives all have dynamic IP addresses, so how do you resolve the current address? TIA

    Comment by Bob — Thursday, 11 February 2010 @ 12:03

  3. Good point, Bob. Most broadband routers these days are capable of registering the dynamic IP address with a dynamic DNS service such as DynDNS. That is what I use.

    You’ll also need to configure the router to allow incoming connections to the NAS. The easiest way to do that is to set the NAS as the DMZ host. The DMZ host is the one that gets all incoming connections for which the router has no other rule. Then you can use passive FTP.

    If you only forward one port to the NAS (e.g. port 21) then you can only use active FTP, which means your own router needs to allow incoming connections to your computer.

    It takes a bit of fiddling to set this all up if you’ve never done this before.

    Comment by Jan Goyvaerts — Thursday, 11 February 2010 @ 17:37

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