Replacing an expensive proprietary CM system with bzr.

[John Arbash Meinel]

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Talden wrote:
> Is there a commentary anywhere in the docs on known scaling behaviour?
> 
> EG number of files/folders in a working tree, size of individual
> files, total size of workign tree, number of revisions, commit
> sizes...
> 
> We have a CVS tree that, in an experimental conversion to Subversion
> produced around 25,000 revisions for a working tree with 17,000 files
> in 3,500 folders.  The working tree totals (not counting any VCS
> book-keeping) 800MB with about 1000 files accounting for 75% of that
> volume.
> 
> There are a couple of dozen branches but I would expect 2/3rds of the
> revisions to be on HEAD.
> 
> I'd be interested in knowing how this might perform in Bazaar -
> obviously I'm not expecting numbers, but are there any known scaling
> issues?
> 
> --
> Talden

Well, Ian is currently working on importing the OOo repository as "one
big tree" which makes it ~75k files, 500k revisions, and several GB of
data. (In SVN it is ~50GB on disk, it was smaller than that in CVS.)
That will be the largest tree I know of which should give a bit of an
upper limit to scaling.

25k revisions is pretty small (Bazaar itself is 15k). 17k files probably
puts "bzr status" at < 2s. (I think on a Moz tree with 50+k files it was
2-3s on decent hardware.)

With 7k files my "bzr status" time is < 1s (0.8s) on 5 year old
hardware. That tree is 131MB with 56k revisions (600MB in the repository.)

You tree shape is a bit different (~2x the files, but 8x the bytes).

Probably my biggest concern would just be having a lot of data as your
history grows large. I don't know how much churn your files have (are
they big compressed binaries which roll over completely with every minor
change, or are they just big text files that have 2 lines change in a
given commit...)

If your history is 2GB, that makes initial copy to a new machine have to
download 2GB of data. We are working on Shallow Branches that wouldn't
copy the data, but then you don't have the history locally for
introspection, etc.

In general, I don't think your tree is in the "running into problems"
size yet. It might be just outside of the "simple comfort" zone.

John
=:->
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