We have a small programming shop of at most 5 people working on a single project. I fully grok why DVCS is better for open source projects, and for large companies, but what advantages does it have for smaller companies other than “you can work on the airplane.” Which would require extra SA work to make sure that our repositories on DEV boxes was properly backed up every night.
We also a have several non technical people (artists, translators) who can (sort of) deal with SVN, in peoples experience how much training is required to get them to move to a DVCS?
I’m going to speak from my experience, which is primarily with SVN and Hg, often working with designers and programmers who are not comfortable with version control.
My big beef with SVN and other CVCS’s I’ve used is that they block you from making commits, not just when the network is down, but also in case of a conflict (or worse, someone locking a file so no one else can make changes to it!). You could of course commit to a branch, but between network bandwidth required to switch branches and the pain involved in merging, you still have a problem.
Of course, SVN blocks you from committing conflicted files so that you don’t accidentally overwrite someone else’s work; SVN requires you to at least acknowledge that you know one version or the other (or a custom combination of the two) is right. Mercurial, however, has a better solution (2, actually):
1. You can always commit to the local repository now and merge later. (All DVCS’s have this feature.)
2. Even if you pull or push conflicting changes, instead of being blocked from committing, you have multiple heads via anonymous branches. (Sorry I can’t really explain this in detail here, but you can google it.)
So your workflow goes from:
1. Get the latest, make changes, test them.
2. Get the latest, resolve conflicts, test the result.
3. Commit.
and becomes:
1. Get the latest, make changes, test them.
2. Commit (so you have a place to fall back to).
3. Get the latest, resolve conflicts, test the result.
4. Commit and push.
That extra commit means you’re doing less work per commit, so you have more checkpoints to fall back on. And there are other ways you can make more commits without getting in others’ way.
SVN is just slow enough to break my concentration and tempt me to go to facebook; mercurial is fast and git is faster. The speed issue becomes very important when reviewing a log or changes to a working copy. With TortoiseHg, I can click through a list of files, and instantly see changes to that file; it takes about a couple seconds per file with TortoiseSVN + WinMerge (not sure how much of this is due to the DVCS). The more I use these tools, the more I feel that a VCS needs to be fast, just like a text editor or a mouse cursor–fast enough that you shouldn’t require the network to do it.
Subjectively, I find TortoiseHg to be a heck of a lot easier to use than TortoiseSVN (or other tortoises I’ve used). TortoiseHg is mutli-platform, too. 🙂
One more thing: As I understand, a SVN working copy is defined recursively: Each folder is a working copy. This allows you to do some fancy-pants stuff (e.g. having a working copy that contains folders from disparate locations in the repository). I don’t know if Hg has a similar feature, but in my experience, SVN’s implementation of this feature causes only problems where I work, especially for those not quite comfy with SVN. When they copy-and-paste a WC folder on their machine via the OS shell instead of via svn copy, it goofs up their WC. I’ve goofed up my WC this way as well. It’s less of a problem with Hg–you normally work with an entire repo at once, whether you clone, update, or commit.