Connecting computers for backup purposes

March 5, 2009 3:39 AM

I have a seperate backup server but would only be able to backup via wifi or cable to another computer - how/what to do?!

I have built a little computer with 2 x 500GB drives and Win XP but it is currently not doing anything at the moment as I am unclear on the best way to connect with other computers.

I have a Belkin adsl wireless router downstairs from which the office computer and laptop connect to for internet and file transfers between them. I have a spare Belkin wireless usb stick that I could use to facilitate some communication but this would only be useful for small files.

Backing up the office computer (about 300GB) would be ridiculous over a wireless connection. It might be ok for incremental backups but sometimes there are quite a lot of large files being generated on the office PC.

The computer already has an ethernet port and would be near to the office computer (hidden away in storage cupboard to prevent theft). I could run a cable under the carpet from backup computer to office computer but what would I use? CAT5?

Ultimately, the aim is to have automated backups so I never need to worry. Thanks for any help you can give!

posted by SRMorris to computers & internet (8 comments total)

Can you run an ethernet cable from the backup computer to the router? If the Belkin router and the computer are rated for gigabit ethernet (not especially likely for a consumer-grade router, not unlikely for a recent computer), make it a Cat5e cable. Otherwise, Cat5 is fine.

Is that storage cupboard ventilated? Operating a computer in a closed cupboard sounds like a recipe for overheating and failure.
posted by Zed at 4:22 AM on March 5

You may find rsync helpful - it will only copy over what has changed (and just the changed parts in large files), so doing incremental backups will be reasonably quick. A version for Windows is on the download page. Note that some files/directories, particularly databases, may not work if you just copy their current running version. Test your backups!

Running rsync automatically every day (say, at 4 in the morning) to incrementally backup will go a long way. You could use the wireless (encrypted connection) or CAT5, but you would need a crossover cable or a hub / switch.

Seconding that the storage cupboard might get hot.
posted by silentbicycle at 4:35 AM on March 5

Newer gig capable machines automagically detect cross-over cable situation. Cat5 over short distances will be fine even for gig. You go 5e when you get close to the 100m mark. Wired is much better than WiFi, probably 100Mb/s at least, 1Gb/s if you're lucky.

rsync is good, feel the pain and do one full copy and then rsync. you may also want to do a 'hot backup' of databases and stuff... sometimes it doesn't work if you just copy the file from disk.

(why yes, I have a dozen cables in my bag for different consoles, and short drops and fiber...)
posted by zengargoyle at 5:08 AM on March 5

If you want anything a little less complicated than rsync, you might try Microsoft SyncToy (free). Works just fine for backups. May not be as smart about incrementals as rsync but ought to be easier to set up if you think rsync looks like too much of a pain.
posted by caution live frogs at 5:58 AM on March 5

If you're thinking about rsync, rdiff-backup, which is built on rsync, could be a great choice. It's what I currently use (on Linux, but it supposedly works on Windows as well). It makes it easy to produce and restore from reverse incremental backups.

Assuming you're using 802.11g, the first 300 GB backup would take... let's see, 54 Mbps = 6 MB/s, and assuming half of that's lost to protocol overhead and less than perfect connection, about 3.4 MB/s, so about 25 hours for 300 GB. That's kind of painful, but it suggests that subsequent backups using an rsync-type solution could finish in a very reasonable time over wireless since it's unlikely the deltas will be larger than a couple of gigabytes.

If you can run an Ethernet cable to both machines, you could maybe double or better that speed. Cat-5 is good. As zengargoyle said, some people will recommend Cat-5e if you have all gigabit hardware, but Cat-5 is fine, especially for shorter runs. Cat-6 is overkill and is mostly useful for future-proofing in permanent installations.
posted by musicinmybrain at 6:31 AM on March 5

I think you will find if you go to most electric supply houses, or even to Home Depot or similar, that the Cat-5/5e argument is moot -- they're not selling much Cat-5 anymore; it's almost all 5e. What you pay extra for now is Cat-6, which I'd recommend if you were running cable in your walls, but probably isn't worth the expense if you're just stringing it across a room (especially in a place where it's likely to be stepped on and ruined in time anyway, like under a carpet).
posted by Kadin2048 at 7:03 AM on March 5

I have a very similar setup. I did upgrade all my NICs and router to gigabit ethernet for faster speed in general (i use it for more than just backup), but "regular" 100 would work fine too. Then I set this app to run at 2am: http://www.rdcomp.net/ezbackitup/ (it's free and REAL easy to setup)

I add my My Documents folder which contains all my music and pictures, then at 2am it checks for changes and if needed, copes those files over the LAN to the dedicated PC. If you have Windows setup on the extra computer, you'd just share the drives and then map them on your client PC.

I went a few steps further and installed freeNAS on the extra PC which ensures I'm not wasting room on the drives with a full Windows or Linux install. http://www.freenas.org/

I also installed a SATA RAID card and a have the two drives setup as RAID1 which in effect means the same thing is written to both, in case one dies, the other has the exact same data. This would in effect be a triple copy for a backup server, but I also use it as a source drive for a lot of media files.
posted by patrad at 7:06 AM on March 5

You could also move the computers close to each other to do the initial backup by cable and then afterwards do the incremental backups wirelessly.
posted by Gomez_in_the_South at 8:00 AM on March 5