Keith,
While I have some spare time, I thought I would go ahead and provide some of the informational groundwork regarding the issue of UIDs. This way, you'll understand
why it is my recommendation that you take direct control of them, how they affect (or may affect) your particular environment, and what benefits you can expect from having the control I recommend. Here we go...
UNIX "thinks" of users according to their UID. While it is true that it also "maps" these UIDs to human-language short names that we can see and readily understand, under that layer of apparent friendliness the operating system still refers to us (users, that is) as "501," "502," etc. As far as the OS is concerned, we
are our UIDs, and most of the applications we run as users are, too.
When we create a file, and this includes the act of copying one, that file is assigned our UID, thereby designating the fact that we "own" it. This UID, along with the permissions set for the file, are contained in "bits" that are reserved specifically for the purpose of controlling the file access. And in UNIX, historically, bits are a precious commodity. It is for this reason that ownership and permissions have always been stored in a spartan and
extremely efficient way.
So how and why would you care about all this, when the GUI layer of OS X typically hides all this "stuff" from you? Well, let's take a look at two of your users, "fred" and "sally." Fred uses an iMac, while sally has a Macbook. Both computers are connected to your network, and both users regularly save files to your NAS. Further, we're going to assume that both fred and sally use accounts that were the first ones created within the installations on their respective computers (in other words, they both used the "Setup Assistant" to create their accounts).
In this case, they will
both have a UID of "501." The files they save to the NAS will be "owned" by a user with the UID "501." Every OS X machine on your network will recognize those files as being owned by "501." Put simply, not only will they
both own the files either one saves, but every user with a UID of "501" (presumably one per machine on your network) will own those files.
At first glance, this scenario might seem ideal for an establishment such as yours, where everyone has their own computer, and it is assumed everyone will be collaborating, each contributing something to the data being generated, and consequently, each needing that "ownership" granted.
But only at first glance. Once
anything changes, the entire house of cards will come tumbling down, and without the
conscious control I recommend you pursue, you won't have any idea why or what is going on. If, for example, you wish to give "fred" your old Macbook Pro, in order to allow him the freedom of a portable machine, you'll probably do so by first creating an account on it for him, then deleting your own. Fred will end up with a new UID on this Macbook Pro. Assuming his is the second account created on it, his new UID will be "502." When he then mounts the NAS volume in an effort to continue his work with his files, he will find that he
no longer is recognized as the owner of those files. What is he to do? He is just a user, and has no knowledge of this stuff. He'll be out of commission, and will be at your desk consuming your valuable time. In turn, you will be coming to us for a "fix," and all the while, no work is getting done.
Worse, he will no longer be recognized as the owner of the files he saved on other external drives (if they exist).
The answer, then, is to gain that conscious control over who gets what UID. Instead of throwing users onto machines willy-nilly, you'll use the same usernames and UID for each of your "humans." This would be a dirt-simple step to take, if you were just now starting from the ground up with all of your machines and staff. As it is, "mid-stream" as you are, it is still a relatively simple thing to pull off. Certainly nothing that you couldn't do in perhaps a couple hours (or less), with access to all the machines in your organization.
The benefits only start with the complete removal of the "oops, I no longer own my files" syndrome. One very powerful option it opens to you is the ability to carry that over into the presence of an account for
every member of your organization on
every machine in your organization. All without the need for OS X server. With this in place, any one of your users can log into any machine, at any time, and have exactly the same access and ownership that they always have, across your entire network.
So far, we have only discussed file
access. Even if you don't right now, you may at some time have a comparable need for file
security. Well, everything stated above applies to this, too. Without a firm grasp on UIDs and ownership, your file security is also at risk. You haven't mentioned security in any of your posts, so I will assume it is not important at this time. Just realize that wrapping your mind around ownership and UIDs, then applying that knowledge, opens the door to having a firm grasp on security, as it suits you.
Scott
