On backups...

[snoopyh42.livejournal.com]

I found out last night that the "Backup Administrator" (this is separate from the "Restore Administrator", but that's another story) at my customer site in San Pedro is of the belief that a full backup should be run only once. Any subsequent backups should be differentials from the original full. This means that their last full backup was sometime before the year 2000.

Fortunately, I'm just a contractor and can give advice, but it's not up to me what their policies are.

ETA: I don't know all the details on their backup scheme or software, but just that statement made me cringe and I thought it was worth sharing.

(x-posted to snoopyh42)

Comments

[wxgeek.livejournal.com]

holy pete.

that's amazing.

[tmesser.livejournal.com]

Errrrr. I thought the standard was something more like full backups once a week, differentials the other six days. At least, that's how most places where I've worked do things.

[egearman.livejournal.com]

At least.

I've worked at one place where it was full once every two weeks and differentials the other 13 days, only because the admin could only be buggered to do a full one that often. I think his excuse was that it required multiple tapes at the time, due to the tape size they used, but can't quite recall.

[doctoreon.livejournal.com]

San Pedro, CA? My home town? Woooo...don't get me started on the stupid to be found there, but I will mention I moved away when I was 19.

[sethb.livejournal.com]

Aren't those differentials getting close to the size of a full?

[gholam.livejournal.com]

Well, depending on what backup system they're using, he could be right. Some programs can do "synthetic fulls" from incrementals.

[egearman.livejournal.com]

Yeah, but if it's not, we're talking a lot of restore work to do. Assuming that there are no tape errors...

[gholam.livejournal.com]

If it's to tape, and backups are differential, then you need the original full and latest differential. If the original full is still intact it shouldn't be a problem.

[egearman.livejournal.com]

*nod* probably was thinking of some backup solution in the past where you needed all the incrementals from the last full.

[gholam.livejournal.com]

If you're doing incrementals, then yes, you need them all. If you're doing differentials then every differential contains all changes from last full, and for a full restore you need full backup + last differential. Nothing old or new about it, that's how backups always worked. High-end backup-to-disk programs can take previous full and a chain of incrementals and compile a new synthetic full without actually running it.

[egearman.livejournal.com]

Gotcha. Been a while since I've had to do anything with backups, other that moving files to the backup area and the occasional taking a CD home during hurricane season.

[thudthwacker.livejournal.com]

So, I'm thinking that the Backup Administrator does not very much like the Restore Administrator.

[jimbojones.livejournal.com]

"ETA?"

Estimated Time of Arrival: I'm a contractor.

Uhhh...

[confectionqueen.livejournal.com]

Edited to Add

[cybirea.livejournal.com]

OMG! I'm frightened for them. That's horrific. ~cries~
Poor restore administrator. :( Sends them hugs...

[jecook]

O.O

that's just..... Gah.

[ptstech.livejournal.com]

That is a true WTF moment right there.

[pat-barron.livejournal.com]

Well, it's not actually a horrible philosophy, depending on how much data you're talking about, and how frequently it changes.

But even if you accept the philosophy, having the last full backup in 2000 is starting to reach the point where you wonder if the media is still good...

(At my place, we do full backups of our fileservers once a month, then weekly and daily incrementals on top of that. We can't do fulls more frequently, because there's enough data that the full backup itself takes close to a week to run....)