The Adventures of Systems Boy!

Confessions of a Mac SysAdmin...

Tiger Lab Migration Part 7: Wiggly-Niggly

Well, we're getting close. We're down to last, wiggly-niggly little tidbits. Here's where we've been in the last few weeks:

The Master System
We have completed a very nice build of Tiger with most of the software we need on all machines, though we're lacking all the most recent Adobe stuff due to not having received the most recent Adobe stuff. 'S'okay. We'll make do with CS1 for now. Our system is all loaded up with our custom scripts, and a new, beefier home account mount script. And it's got a nice, big, 75GB system partition. Why, it's just swell.

We've used this system to clone to all our other lab machines. We boot these other machines in firewire target disk mode, and then we use Disk Utility to restore the Master System to the new machine's system partition. Or, we wanted to use Disk Utility. Turned out that our first Disk Utility-cloned system had some problems due to -- yep, you betcha -- Tiger bugs. The problem was that Disk Utility wasn't blessing the new system partition, so when we'd boot the new machine, we'd get the flashing question mark of doom. So we'd have to then boot off the Tiger install disk, and set the new system partition on the newly built machine to be the startup disk. I decided this was a pain, and that it would be much easier and more instructional to do our clones with a tiny, tiny shell script that calls ASR (Apple Software Restore, via the asr command).

#!/bin/bash

## Script to Clone Local Volumes ##
## systemsboy - Aug 18, 2005 ##

clear

## Define Variables ##

echo "
Please enter the path to the SOURCE volume or ASR-ready disk image...
(Example: /Volumes/MyVolume)"
read SOURCE

echo "
Please enter the path to the TARGET volume...
(Example: /Volumes/MyVolume)"
read TARGET

## ASR Portion of Script ##
echo "
Building Clone... Please wait...
________________________________
"
sudo asr -source "$SOURCE" -target "$TARGET" -erase

exit 0


This did the trick indeed, and was as easy to use, if not as purdy, as the Disk Utility application. This method only yielded one problem, and that was that all the invisible folders -- /var /etc /private and the like -- were not made invisible on our cloned systems. This is another Tiger bug, but one that was fixed in 10.4.2's version of Disk Utility. Apparently not fixed in ASR from the command-line, however. This problem yielded both an intersting solution, and some interesting information. Back in the day, these files were made invisible to the Finder by the magic of the .hidden file. The .hidden file was simply a list of files or folders at the top level of the root drive that should be treated as invisible by the Finder. Want to make something invisible on /? Just add it to the .hidden file and restart the Finder. (Ironically, the .hidden file was also at the root level of the system, but was rendered invisible by the fact that its name began with a period.) Nowadays, however -- in Tiger, that is -- this is no longer that case. Files on root are now made invisible, according to this Apple KBase article, by setting certain file attributes. I'll tell you, I have yet to figure out what those attributes are, or how to modify them, but when I do I'll shout. In the interim, I was forced to locate the "SetHidden" program on my original Tiger install DVD. After insering the DVD, it can be found at:
/Volumes/Mac\ OS\ X\ Install\ DVD/System/Installation/Packages/OSInstall.mpkg/Contents/Resources/

I've now copied this file to a folder called SetFile, which I've placed in the Applications folder for future use. Also, I needed the hidden_MacOS9, which can be found, and should be placed, in the same folder as the SetHidden command. So I now have a folder in my Applications folder, called SetHidden, in which the SetHidden command and the hidden_MacOS9 files reside, installed on my master, and I've added the commands:
cd /Applications/SetHidden
sudo SetHidden /Path/To/My/Clone/System hidden_MacOS9

to my shell script, and voila! Clone script complete!

#!/bin/bash

## Script to Clone Local Volumes ##
## systemsboy - Aug 18, 2005 ##

clear

## Define Variables ##

echo "
Please enter the path to the SOURCE volume or ASR-ready disk image...
(Example: /Volumes/MyVolume)"
read SOURCE

echo "
Please enter the path to the TARGET volume...
(Example: /Volumes/MyVolume)"
read TARGET

## ASR Portion of Script ##
echo "
Building Clone... Please wait...
________________________________
"
sudo asr -source "$SOURCE" -target "$TARGET" -erase

## Set Hidden Files (Tiger Bug Workaround) ##
echo "
Mac OS X 10.4 does not properly set hidden files.
We will now use the SetHidden command to rectify the problem.
For this step, the SetHidden folder must be present in /Applications.
---------------------------------
"
cd /Applications/SetHidden
sudo ./SetHidden "$TARGET" hidden_MacOS9

exit 0


Cloning all 14 systems on the floor took my Lab Assistants a few short hours.

Spotlight
I mentioned some concerns regarding Spotlight and the particular way in which users use our lab. After some mucking around, and testing of various methods of disabling Spotlight, both forced and optional, I've decided to do nothing. I do this kind of thing all the time. Worry and worry about something, and then, finally, throw caution to the wind and do nothing about it. It's my way. It's part of what makes me so gosh-darn lovable. But I do have two things behind that decision: a rationale, and a backup plan.

The first problem I'd anticipated was that Spotlight would begin indexing user home accounts over the network all at once as soon as everyone logged in, and that this would cause problems with network performance and incomplete indexes. Upon further reflection (read: obsessing), I decided that that Spotlight's network resource usgae would probably be low, and that it would probably avoid incomplete indexes by either continuing in the background after logout, or by resuming at next login. Also, since home accounts have quotas, the largest of which is 7 GB, indexing shouldn't take too long, and any problems should be quickly mitigated.

The second possible problem I'd worried about was that Spotlight's insistance on indexing firewire drives would take forever to yield complete indexes on large drives -- a process that would likely be interrupted at logout before it was complete -- leaving many users with partially indexed drives. In my tests, however, Spotlight picked up right where it left of with drives that were partially indexed when ejected and then re-mounted, so I'm not convinced this will even be a problem. I also worried that Spotlight's firewire drive indexing would cause performance problems that would incapacitate users who were working on video. This may yet be the case. We'll know soon enough.

I came up with a number of possible solutions to these problems, all messy, all imperfect. Ultimately, I decided that the best option was to wait and see what problems arose, and then tackle those problems with the most appropriate of the solutions I devised. Who knows? Maybe it will all work out great without any intervention from me. And that'd be just ducky.

Network
We have an intersting and complex network. It consists of Mac, Linux, and Windows machines, a network RAID, and web and mail storage. And all of this is accessible, in one way or another, via the network. The problem comes when you try to explain all this to new (or sometimes even old) students. It's not an easy picture to paint. And overwhelmed first years usually don't quite catch on for some time. But as we design our network, and build our systems, we're very concerned about how all that is presented to the users. And we try to make it as simple and as understandable as possible, which is, after all, the Mac way, and is why people love the Mac. So let me just say, right here, right now, what the fuck is up with the "Network" view? That piece of shit gets worse with every OS revision. And no one seems to care. I can't find diddly about it on the forums.

So here's the background on this outburst. Back in the Panther years, the Network view offered up a pretty nifty way to present a great deal of our network -- the shared drives of all platforms -- to our Mac users. The coolest part was that it looked much like what you saw on Windows, which simplified things greatly by presenting a consisten network view across platforms. There were a couple things that made this possible. One was SMB workgroup names. SMB does a great job of not only sharing files, but broadcasting itself as a service on a network. Setting up computers under SMB with a workgroup name based on the platform of the given machine got all our Mac, Linux and Windows computers grouped appropriately on the network. And Mac can read those groups and smartly creates folders in the Network directory named after those groups and populated with the systems that belong to them. So in my Network browser, there'd be a folder called "Linux," and all the Linux computers would be in there. Same for Windows. Here's the catch: Our Macs share via SMB to Windows, but we want them to share via AFP to other Macs. Personal File Sharing, which uses AFP, does not, by default broadcast any kind of grouping. If you turn on AFP, you just broadcast the service, but you can't specify it's appearance or where on the client the shares will appear. Computers broadcast via AFP in Panther just show up in the "local" folder, not in a "Macs" folder like their SMB sharing counterparts. There was, however, a sneaky way to define this in Panther, by editing a little file called /etc/slpsa.conf, and thereby magically creating what are known as SLP scopes. In fact, SLP scopes are just that -- a way to group a particular service from a particualr device into logical groups. So we scoped our Macs to the "Macs" scope and they showed up in our "Macs" group in /Network, and all was well in the universe. If you're unbearably astute, you'll probably be wondering why, though, our Macs, when connecting to other Macs via the "Macs" scope in the Network folder, didn't connect to said Macs via SMB rather than AFP. And here was something amazingly cool in Panther. Panther smartly dealt with the folder full of Macs in our Network view. So, when it saw these other Macs broadcasting and sharing over two protocols -- AFP and SMB -- it intellegently chose the best one, which for a Mac was AFP, of course. That was the thing of beauty that allowed us to present the same view of the entire, heterogeneous network the same way on all platforms while still allowing us to connect with different protocols. It was frickin', frackin', goddamn sweet, is what it was. Brilliant. And now it's gone.

Not only is this intelligent decision making gone from Tiger, at least in the latest incarnation (10.4.2 as of this writing), but so too is the ability to define SLP scopes. So, this means two bad things: 1) I can no longer define specific locations for my AFP-shared Macs, and 2) any connection made via the "Macs" folder in the Network folder (which, remember, is now only defined by SMB, not by SLP) connects via SMB; my Macs connect to each other via the Windows file sharing protocol, which is a big fat problem.

So, I'm currently trying to devise a way to scope the Mac shares into some sort of logical grouping that will allow me to present those shares in a palatable way. But it ain't easy. I know you can do this with Tiger Server, and this is probably why they've crippled it on the client, but I don't a Tiger Server yet, and I'm hesitant to build one this close to the beginning of the semester. So we shall see...

The migration is nearly complete. Time permitting, I would abasolutely love to build a fresh new Tiger Server. I'll probably give it a shot in this last week before classes begin, but I'll be sure and keep a clone of the existing Panther Server in case things go awry. Beyond that, and the aforementioned wiggly-niggly, we're done. We're upgraded, on the workstations anyway. And it is good.

There will, most likely, be problems that arise once the students come in and start using the new systems. I will share those in a later post. Until then...

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10:35 AM

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