When a project has been on the go for a while theres going to be all sorts of stuff in there from jars to zips and everything in between.  We went though this a while ago and wanting to keep all the history, we needed a way to prune the history of all the big files and weird things we were not going to move to git.

Now we knew we had some large files, namely binary files like jars which were build dependencies before we moved to artifactory for a lot of it.  So, before we start we need to make sure that git is installed, and git-lfs.  Git-lfs should be on the path so git can find it and you'll need to make sure git svn can run.  You'll need perl and  to run cpan (Comprehensive Perl Archive Network) to install the SVN::Core modules.

Initialisation

As a test to start, make sure git and git lfs are on the path and that git svn runs.

Clone Empty GIT Repository

Before the migration, we should create an empty repository for importing the subversion repository into.  Then we can clone it to start the migration

git clone git@gitlab.yourcompany.com:group-name/gitrepo.git 

Clone the subversion repository into the empty git repository

svn log -q | awk -F '|' '/^r/ {sub("^ ", "", $2); sub(" $", "", $2); print $2" = "$2" <"$2">"}' | sort -u > authors.txt 

Now we need to edit that file which has a format like this

git svn clone https://server.company.com/svn/project/trunk gitrepo --authors-file=authors.txt > loglog 2>&1 

We push the output into a log file because it takes ages and you can scroll back and see where the actual clone is.  This pulls the entire history from revision 1 to HEAD and drops it into the git repository

Clean up the GIT Repository Metadata 

Now, we use a really handy utility: BFG: Removes large or troublesome blobs like git-filter-branch does. For this exercise we run the utility twice. Once to strip blobs larger than 1M

java -jar bfg-1.13.0.jar --strip-blobs-bigger-than 1M git-repo 

Now fix the changes into the repository. 

cd git-repo && git reflog expire --expire=now --all && git gc --prune=now --aggressive && cd - 

Now for the second run of the BFG, we want to convert a bunch of things like binary files to Large File Storage

java -jar bfg-1.13.0.jar --convert-to-git-lfs "*.{rar,dll,zip,war,gz,jar,tar,opar,dmp,serial,exe,mde,gif,msg,oxd_db,dylib,so}" --no-blob-protection git-repo 

And fix that into the repository too.

cd sql-developer && git reflog expire --expire=now --all && git gc --prune=now --aggressive && cd -  

Install and Configure GIT LFS

$cp lfsconfig git/.lfsconfig 
$cat .lfsconfig
[lfs]
 url = https://artifactory.yourcorp.com/api/lfs/git-lfs

Now, you need to install lfs into the repository.

cd git-repo && git lfs install 

and then track all the binary and large files you want

git lfs track *.{rar,dll,zip,war,gz,jar,tar,opar,dmp,serial,exe,mde,gif,msg,oxd_db,dylib,so}  

Commit and Push

Next we need to add the files we just edited AND the base directory of the git repository as all the binary files will be swapped out to LFS on push

git add .lfsconfig .gitattributes && git add .

git commit -m "initial commit to git" && git push origin master  

Depending on the security setting of your artifactory repository you may be prompted for a username and password for pushing the binary files to LFS and then the references and files will be pushed to your remote git repository

Summary

It took us a couple of goes to get this right so we put it in a file to rerun when it died (it will til you get all the large file extensions listed)
Heres the contents of that script you can grab and use for your migration.
Have fun.