Snow Leopard Server

September 2, 2009

Well, the Internets are ablaze with people’s thoughts regarding Snow Leopard, Apple’s desktop OS. Mostly in debate regarding whether it’s worthy of being a paid upgrade. Personally, I think it will, but it’s a chicken or the egg problem at present. End users will get value when apps start taking advantage of its underlying technologies like Grand Central Dispatch, OpenCL and QuickTime X. However, developers aren’t going to make their code dependent on those technologies until Snow Leopard reaches a certain level of penetration, so it’s up to the Apple hype machine to help things hit critical mass.

That’s not what I want to talk about though. Plenty of other places discuss it at length. If you want the super-techy breakdown, Ars Technica has their typically superb article up. What I want to discuss is a version of OS X not as many people play around with, OS X Server. Snow Leopard Server, like its predecessors, contains everything the desktop version does, and also has some of its own server oriented enhancements.

Some of the biggest improvements to Snow Leopard server happen before you ever get to the first login screen. The first is pricing. Traditionally, OS X Server has come in two licensing varieties. There was 10-Client Server for $499 and Unlimited Client Server for $999, the latter of which came standard on all Xserves. The client limit always seemed kind of random and pointless to me, since unlike Windows CALs, the only thing this affected was the number of concurrent AFP connections. Not exactly a big deal, and if the particular server in question wasn’t going to be providing file sharing services, the Unlimited Client version was entirely pointless. Apple, in their usual vein of wanting to keep things simple, has changed the pricing for Snow Leopard Server to just a single Unlimited Client version. What’s more surprising is that this version comes in at the $499 price point of the previous 10 client version. This easily shaves $500 of a lot of the pitches I get to make for installing a workgroup server in situations where an Xserve would be overkill.

Another welcome install related feature is Migration Assistant. Huh? Didn’t they invent that during Panther when the G5 first came out? Yes indeed, but the feature was never present on OS X Server. The logical assumption was that servers are much more complex beasts than a desktop system, and attempting to migrate one’s entire config automatically was asking for trouble. Naturally, I was skeptical when I saw this feature in Apple’s upgrading and migration documentation. At home, I was moving up from a Dual 867mhz Mirrored Door G4 to a brand new Mac Mini. I had every reason to expect this to go to hell in a handbasket, but imagine my surprise, then joy when each and every service I had installed came up, running, and configured just as they were. Even bitchy Kerberos was humming along happily in its new home. I was practically beside myself, this is going to save me a hell of a lot of time.

Apple continues its steady march toward a full-featured competitor to Microsoft Exchange by updating iCal Server and adding the last major piece, Address Book Server. Both of them use open source WebDAV-based systems to provide, respectively, network based calendaring and contacts. These are backed up by the new Push Notification service to deliver the “push” experience many customers are familiar with when using the iPhone with MobileMe or Exchange. While it’s nice to have these services included with the system, and they are easier to configure than the previous iteration of iCal Server, they are still nascent and not well supported outside the Mac and iPhone. Presently, Kerio MailServer is still a much more mature, easy to use and fully featured groupware solution for the Mac, but I am eager to see how far Apple takes these baked in services. I have not been able to test the Mobile Access service since I don’t have the infrastructure for it. It isn’t quite what I was expecting, and is basically a specialized HTTP proxy for iCal, Address Book and Mail. I was expecting it to be a MobileMe like web interface for those services as well as shared folders (like the web version of iDisk). Unfortunately, that was wishful thinking on my part.

It’s difficult for me to directly compare speed to Leopard, as the speed boosts in my home network are most likely due to the swap out of hardware. Snow Leopard Server does seem to run smoothly in the Mini with 4GB of RAM. My typical behavior of having it running torrents while simultaneously allowing me to play back video files over AFP is noticeably less trouble than it was previously. I’ll have a better grasp of the performance differences between the two once I start upgrading Xserves and Mac Pros from one OS to the other.

That about does it for my early thoughts on Snow Leopard Server. As with the desktop OS, it’s a lot of back end speed enhancements and little tweaks that will become more important as we move forward. The new pricing is very attractive though, and I am genuinely happy to have that Migration Assistant (and that it actually works).

I hate Time Capsules

April 7, 2009

With the introduction of Mac OS X 10.5 “Leopard”, Apple released their built-in backup software Time Machine. Time Machine just runs in the background, automatically copying your precious data to another drive. A great idea, now it’s easier than ever to get people to back up. But what about laptops?

Laptops are a huge part of the computer market today, especially for Apple. The problem is that they are, by nature, mobile and not likely to be chained to a desk with an external hard drive hanging off. That means people have to remember to plug that drive into their laptop from time to time, introducing a factor of human error and forgetfulness. There must be a better way right? Isn’t there a way to make backup as wireless as the rest of the laptop? Apple thought so, and released Time Capsule, an Airport Extreme base station with a hard drive built in. Leopard detects Time Capsules on the network and backs up to them over your wireless network with the one-click ease Apple is famous for. There’s just one teensy, weensy little problem:

HFS+ sucks

For those unaware, HFS+ is the file system used by Macs. That is, the organizational system by which the computer keeps track of where and how your data is stored on the actual disk. The problem is, it dates back a long time and as needs have grown, it has started to falter. Big drives with lots of files, especially that change all the time like on Time Machine, make a wreck of HFS+’s catalog. When that catalog gets messy, the drive starts running slow, or may develop problems accessing certain data. The traditional Mac fix for this has been Alsoft’s Disk Warrior, a miracle piece of software that takes your HFS+ catalog and rebuilds a nice clean one. Note, not fixes it, makes a new one. All nice and perfectly organized. Disk Warrior is almost critical on Time Machine drives just due to the sheer number of changes as data is added hourly, and old snapshots are removed. Eventually, all Time Machine drives are likely to need this done.

The issue on Time Capsule is that there’s no way to run Disk Warrior on it. Disk Warrior needs to unmount the drive and have direct access to it. How can you do that when it’s attached over a network? Well, you can’t. Not unless you gut the Time Capsule and attach its drive right to your computer. There’s another problem too. There are actually two HFS+ filesystems you need to worry about. The first is the one on the Time Capsule’s actual drive. The second is the one within the sparse disk image that your backup data is written into. Time Capsule (as well as network Time Machine backups to OS X Server) create a virtual drive as a sparse disk image to back up to, and since this is its own virtual volume, it has its own filesystem to worry about. If either filesystem has problems, your backup fails. Disk Warrior is able to rebuild the filesystem within disk images, and should be able to do it if you mount the Time Capsule’s drive as a shared folder. However, you still can’t rebuild the filesystem on the actual physical drive in the Time Capsule.

The worst part about it is that Apple sells this thing to lay users as a completely turn key system. Set it and forget it. That’s great until HFS+ eats its own tail, then what? Then you call your local Mac IT guy (me) to try and fix the damn thing. If it’s just the sparse image, there is hope. If it’s the filesystem on the drive, probably going to have to format it. It’s really frustrating to see people getting hit like this, from the random home users that call my office to the likes of Wil Wheaton. If your Time Capsule backup has stopped, and rebooting hasn’t solved it, I almost guarantee this is the problem. If your regular, local Time Machine backup has similarly stopped, this is probably the same issue, but at least that’s fixable.

Apple. For the love of god, get us a new filesystem that can actually handle your backup scheme. I am tired of dealing with this.

Update: In addition to the incident that prompted the writing of this post, just as I finished up somebody else walked in complaining that he can’t back up to his Time Capsule. Gee, I wonder what the problem is?