It wasn’t complimentary, but I hardly consider myself or what I write here above criticism, so that’s not a problem in and of itself. The message was in response to my January 14, 2005 Backup Reminder, and because it does contain some valid points, I wanted to reprint it here.
From your blog, “The Geek Girls say that a differential backup copies the files which have changed since the last full backup and that an incremental backup copies the files which have changed since the last backup of any kind. (Are you confused yet? I am.)”
What’s to be confused about? It works exactly the way they say.
-You make a full backup on Monday
-On Tuesday, you change 1 file and back it up only. That’s Differential
-On Wednesday, you change 1 more file. Now, if you back it up and the one from yesterday, the only changes made since the last full backup, then that is Differential. If you only back it up and not the one from Tuesday, then that is Incremental.
That’s actually the clearest explanation I’ve heard of the distinction between differential and incremental backups.
Since when is a RAID system even similar to LIVE BACKUP? (“LIVE BACKUP is a term I found on a database backup site, and it refers to a continuous backup process, where backups are made as the files are changed. This is similar to what happens in a RAID system”) BACKUP backups data. RAID provides data recovery ability, not a backup.
I understand RAID much better now than I did in January of ’05 (which isn’t saying that much, as the Ur-Guru is now trying to explain parity bits to me after reading this post) and I agree that while some configurations of RAID duplicate your data as its created—and some people rely on that instead of instituting real backup systems—what RAID is really designed to protect against is disk failure, not the corruption or loss of data. If you delete a file on one disk, it will get deleted on the other disks in the array. If the file is corrupted, the corruption will be duplicated. So it’s not really a backup.
Yet the similarity between RAID and “live backup” or “continous data protection” (as most people seem to call it these days) should be obvious: the duplication happens when the data is changed, continuously, in the background where you don’t notice it.
That’s the useful part of the message. It’s followed by the snide part:
If you don’t know these simple basic facts and prefer to wing it by just using your own terminology (“Personally, I like the term “Differential Backup,” and that’s what I use to describe the way my own file backups work.”), then you have no business in the IT field. You’re an embarassment to the rest of us that do know our business and take it seriously.
Don’t bother replying (especially since this is a null address used for spammers). Either get out of the field or learn your craft properly.
Well, Thomas, or Rick, or whatever your name is, you might be relieved to know that I’m not in the IT business. I do provide some general-purpose consulting to home office computer users, based on having more experience than they do and being able to call on the Ur-Guru to answer questions I can’t. But I don’t claim to be a real IT professional, and I don’t want to be an IT professional.
I’m a writer. I’m writing a column, which I research to the best of my ability given the constraints on publishing it and the fact that I’m not getting paid for it. I correct mistakes when I’m made aware of them, but I don’t have every past post memorized, so unless I get new information shortly after publishing something or people point out errors, they may stay in the blog.
There are countless other people out there who know more about technology, and specifically about backups, archives, and data protection, than I do. None of them seem to want to write a weekly e-zine/blog exclusively devoted to the subject. And persistence usually wins out over genius.
The point of the Backup Reminder is to get people to back up their data. If they need to hire a real professional, and not me, to get that set up for them—all the better. But those who do hire me can at least be assured that I won’t treat them with contempt just because they don’t know as much as I do about something.