Daily Archives: November 7, 2008

Search for Backup Tools

Software

Since the last time I went looking for backup software, I’ve still be using rdiff-backup.

It’s nice, except for one thing: it always keeps an uncompressed copy of your current state on the disk. This is becoming increasingly annoying.

I did some tests with dar and BackupPC, and both saved considerable disk space over rdiff-backup. The problem with dar, or compressed full/incrementals with tar, is that eventually you have to make a new full backup. You have to do that, *then* delete all your old fulls and incrementals, so there will be times when you have to store a full backup twice.

The hardlinking approach sounds good. It’s got a few problems, too. One is that it can lose metadata about, ironically enough, hard links. Another is that few of the hard linking programs offer a compressed on-disk format. Here’s what I’ve been looking at:

BackupPC

Nice on the service. I’m a bit annoyed that it’s web-driven rather than commandline-driven, but I can look past that. I can also look past that it won’t let me clamp down on ssh access as much as I’d like.

BackupPC writes metadata to disk alongside files, so it can restore hard links, symlinks, device entries, and the like. It also has the nice feature of being able to hard link identical files across machines, so if you’re backing up /usr on a bunch of machines and have the same files installed, you save space. Nice.

BackupPC also can compress the files on your disk. It uses pre-compression md5sums for identifying files to hard link, which is nice.

Here’s where I get nervous.

BackupPC doesn’t just use regular compression, from say gzip or bzip2. It uses its own low-level algorithm centered around the Perl deflate library. And it does it in a nonstandard way owing to a supposed memory issue with zlib. Why they don’t just pipe it through gzip or equivalent is beyond me.

This means that, first off, it’s using a nonstandard compression format, which makes me nervous to begin with. If that weren’t annoying enough, you have to install Perl plus a bunch of modules to extract the thing. This makes me nervous too.

Dirvish

Doesn’t support compression.

faubackup

Doesn’t support compression.

rdup

Supports compression and encryption. Does not preserve ownership of things unless the destination filesystem does (meaning you must run as root to store your backups.)

Killer lack of feature: it does not preserve knowledge about what was hardlinked on the source system, so when you restore your backup, all hardlinks are lost. Epic fail.

rsnapshot

Doesn’t support compression.

StoreBackup

Does support compression, appears to restore metadata in a sane way. Supports backing up to a different machine on the LAN, but only if you set up NFS. Looks inappropriate for doing backups over VPN. Comprehensive, though confusing, manual. Looks like an oddball design with an oddball manual.

So, any suggestions?

Wow

Politics

People often talk about “memorable moments” — times where pretty much everybody in the country remembers where they were at that exact time.

There are probably only two of those moments I can remember: the 1989 earthquake during the World Series and the time 9/11 happened. My car was in for service that day, and I was sitting in the lobby of the mechanics watching it on TV.

So now I have a third: watching Barack Obama win the presidency.

We were installing some new blinds in the kitchen while listening to the coverage on NPR, periodically going over to the office to watch the TV coverage on the computer. (Our TV is upstairs right now, so that was more convenient.)

A few minutes before the election was called, I remember Brian Williams saying something like “We’re going to go to local stations now, but you better not walk away. We’ll have some amazing news at the top of the hour.”

We watched that announcement, then saw McCain’s speech, and finally Obama’s speech (missed the first minute or two of it actually). What an amazing evening.

Then seeing the stories of people celebrating all around the country and around the world: the impromptu party in front of the White House Tuesday night, the small gathering at the Lincoln Memorial Wednesday morning, the Obama parties all around the world. And we watched it on TV in our house while Jacob slept. I feel like I missed out somehow.