John Altman writes: >We've been struggling a bit with how best to set up backup of a group >of Macs about the same size that you are talking about. In the past, >we've had problems with slow networks (although this week we moved >into a new building, and I think the network is faster), and also a >host of other problems. Following is a barrage of questions that I'm >sending to you personally (not to the group), but perhaps it would be >useful if you replied to the group (if you have the time). > >1) What sort of tape drive do you use for 15 Macs, and what is its capacity? >2) Do you do incrementals or always full backups? >3) Do you run into problems with slow networks, and the backups not >actually finishing? >4) Do you have a dedicated backup server, or do you use a machine >that is in use everyday? Hi John (and the rest of the Flow group!) [By the way, an addendum to using backups: we have successfully used backups to eliminate viruses: we simply restore the computer disks to the state they were in the day before the infection, and the restore only uninfected applications or files that are dated after that date. This has made us much less leery about viruses, and, in fact, do not run virus protection software on most of our computers. While I do NOT recommend eliminating virus protection software, it is useful to note that nightly backups greatly reduce the amount of damage that viruses can do.] In response to your questions: (1) We use CD-R. Several reasons: it's much faster, it's much easier, it's much cheaper, it's easier to store. The only downside is the smallish storage capacity (~650 Mbytes, which gest doubled to 1.3 by software compression). This means the first time you do a full back up, you will need to have someone sit there and feed disks continuously. Incrementals, however, take much less space; we use about 1 disk per week. The final advantage of CD-R is that we can write our own (personal disks) whenever the backup isn't running--like during the day. We can write music disks, data disks, etc... (2) We do a full backup about every 6 months, with incrementals happening automatically every night. The incrementals are done only on user folders (we actually partition our disks in 2; one partition is System + Applications; the other partition is user files). System partitions are backed up weekly instead of daily. In addition, we specify that certain folders never get backed up: for example, any folder with the word "cache" or "temp" in it will not be backed up. This relieves a lot of backing up of, for example, browser files which are temporarily stored on disk and are not necessary to backup. Retrospect allows you to mirror your backups (i.e., to keep 2 fully independent backups going); this gives you two copies you could store in separate locations. Again, the only downside is that either you have to buy 2 CD-R's (not that expensive!) or have someone switch disks more frequently. (3) No, we don't. The incrementals run at 3 a.m., where the backup is fast. Also, Retrospect maintains an extension on each remote Mac which does most of the work, so, in reality, only the small changed files have to be transferred over the network. The full backup does take a lot of time and can be slowed during heavy network traffic. However, again, Retrospect can be scheduled so as to only run during certain times (or at any time); it is smart enough to backup devices that didn't make it into the last window at the next opportunity, etc. BTW, I'm pretty sure that you can also tell Retrospect to backup portables that are intermittenly connected to the network--whenever it gets connected, it sends a message and Retrospect fires up and immediately backs it up. Retrospect is fabulous in its variations and power--but is very easy to setup and use! (4) Yes, we dedicate an older macintosh to this (a powerPC performa). Any PowerPC that you have relegated to lower duty because you bought a new G3 is perfectly fine. Consider the costs, though: buying a new Mac is only about $1200. You'll spend about $500 on a CD-R (because you want at least 4x write speed; 8x is even better!), and then you'll spend up to $1.50 per CD. We typically use about 50-100 CD's per year, but we are not backing up FACS data. (You'll have to figure out how much you need)... in any case, the cost of the CD's is relatively minor. All in all, <$2K for a complete backup system (including the cost of Retrospect plus the remote licenses) is a tiny price to pay for the security of backups. You might even want to consider (re pt. #1 above) to use DVD-R, since capacity is much greater. It increases your cost, but it makes the whole system much less hands-on, since disks have to be changed MUCH less frequently. I would NOT go with CD-RW (or DVD-RW, if it's available), because (1) the cost is much greater, and (2) the idea of backups is that they are permanent! Before buying any backup device, go to the Retrospect web pages (www.dantz.com) and figure out which ones are currently supported. mr
This archive was generated by hypermail 2b29 : Wed Apr 03 2002 - 11:53:48 EST