(r4) VoluteTransfer20150730 < IVOA

IVOA Web>TWikiUsers>DaveMorris>VoluteTransfer20150730 (revision 4) (raw view)~~EditAttach~~
---+ Volute transfer

Options for transferring [[https://volute.googlecode.com][Volute]] from
[[https://code.google.com/][GoogleCode]] to [[https://github.com/][GitHub]].

---+ Headline figures, based on disc usage

---+++ volute-complete - 825M

Svn checkout of everything in the repository.

<verbatim>
    svn checkout https://volute.googlecode.com/svn/trunk/ volute-complete
    du -h volute-complete > complete-original.txt
</verbatim>

---+++ volute-noextern - 764M

Svn checkout, without resolving the extern references.

<verbatim>
    svn checkout --ignore-externals https://volute.googlecode.com/svn/trunk/ volute-noextern
    du -h volute-noextern > noextern-original.txt
</verbatim>

---+++ volute-export - 391M

Svn export, a snapshot of the current state with no commit history.

<verbatim>
    svn export --ignore-externals https://volute.googlecode.com/svn/trunk/ volute-export
    du -h volute-export > export-original.txt
</verbatim>

Of the 391M in the exported snapshot, the top 8 projects are :

   * theory 220M
   * dm 126M
   * registry 26M
   * grid 6M
   * vocabularies 3M
   * samp 3M
   * votable 2M
   * ivoapub 2M

---+ Maximal transfer

If we just press the 'export to !GitHub' button, then everything will get
transferred, including the commit history.

I have seen this work on a *small* project, and everything just worked.
On a large project like ours the process will probably take a while.

With a total size of 825M we are close to the !GitHub 1Gbyte per repository
limit, which may cause problems later on.

The only unusual thing to watch for is that the email telling you the
process has completed will be sent to the email address linked to your
!GitHub account, not to your Google account.

See: [[https://code.google.com/export-to-github/][GitHubExporter]]

---+ IVOA organization

If we want our !GitHub repository to be owned by the
[[https://github.com/ivoa][IVOA organization]] in !GitHub, do the transfer
to your private account, and then transfer the repository afterwards.

See: [[https://code.google.com/p/support-tools/wiki/GitHubExporterFAQ#Can_I_migrate_a_Google_Code_repository_to_a_GitHub_Organization?][Migrate to an Organization]]

---+ Commit history

It is important to note that the automated 'export to !GitHub' tool is the
only realistic way to preserve the commit history of the svn reposiroty.

All of the alternative suggestions outlined below rely on a manual process
of exporting the contents to a local copy and then importing some or all
of it into one or more !GitHub repositories. If we decide to go for one
of these alternatives then it is not practical to try to preserve the svn
commit history.

---+ Snapshot transfer

If we skip the svn history and just take a snapshot of where we are now,
then we have less than 400M to transfer.

We would have to do the transfer manually, exporting a local copy from svn,
and then importing it into a new !GitHub repository.

<verbatim>
    git clone https://github.com/YOUR-USERNAME/YOUR-REPOSITORY local-repo
    svn export --ignore-externals https://volute.googlecode.com/svn/trunk/ local-repo
    pushd local-repo
        git add .
        git commit -m 'Initial import from svn'
        git push
    popd
</verbatim>

---+ Space limits

!GitHub don't have hard and fast limits on the size of a repository.

<verbatim>
    We *recommend* repositories be kept under 1GB each. This limit is easy
    to stay within if large files are kept out of the repository. If your
    repository exceeds 1GB, you might receive a polite email from GitHub
    Support requesting that you reduce the size of the repository to bring
    it back down.
</verbatim>(emphasis mine)

See: [[https://help.github.com/articles/what-is-my-disk-quota/][What is my disk quota ?]]

I contacted !GitHub to see if there would be an issue with us using more
than 1Gbyte of space.

I got the following reply from a member of their help team :
<verbatim>
    Hi Dave,

    Thanks for reaching out! We strongly recommend keeping repositories under
    1GB in size. Additionally, to ensure that repository performance is optimal,
    only files less than 100MB in size can be pushed to GitHub.com.

    More information about this can be found here:
    https://help.github.com/articles/what-is-my-disk-quota

    The good news is that in order to make working with large files better,
    we recently published an extension to Git called Git Large File Storage,
    and support for Git LFS is currently in early access on GitHub.com.

    You can check it out at http://git-lfs.github.com and sign up for early
    access at https://github.com/early_access/large_file_storage

    I hope this information helps, please let us know if you have any questions!

    Cheers,
    Rachel
</verbatim>

---+ Large files

I suspect that due to the way that we use volute, the
[[https://git-lfs.github.com/][Large File Storage]] extension will be of
limited value to us.

In the current version of the Git LFS extension you can't select which
files should be stored separately based on file size. The file selection
criteria is based purely on file path and type.

A number of people have been asking for selection by size, but it does not
look like it will be available soon.

   * [[https://github.com/github/git-lfs/issues/125][Add files to git-media by attribute such as size?]]
   * [[https://github.com/github/git-lfs/issues/282][Support tracking by file size]]
   
This means that in order for it to be useful in reducing the size of our
repository, we would need to identify which files we wanted to be handles
using the LFS extension *before* they were added to the repositiory.

In reality, some of our uses would be extremely careful about making sure
every =pdf= and =doc= file in their project was listed, even the ones that
were less than 1Mbyte.
Other users would just want to be able to commit and push a whole directory
tree and leave it up to the software to sort out which files need to be
handled differently.

!GitHub has a maximum file size limit of 100M per file.
The LFS extension was designed to enable Git to handle things like binary
image files, e.g. =jpeg=, =png=, =svg=.
Using the file path and type to identify which files should be treated
differently.

Looking the files in the current volute repository, we have a wide variety
of different file types and sizes, and it would be difficlut to define a
reliable selection criteria to identify which files should be handled by LFS.

   * We have no files larger than 100M bytes.

   * We have no files larger than 50M bytes.

   * We have four files larger than 10M bytes, all of them in the theory project.
      * projects/theory/snap/simtap/PDR143/PDR143-2.vo-urp
      * projects/theory/snap/simtap/PDR143/html/PDR143-2.html
      * projects/theory/snap/simtap/PDR143/tap/PDR143-2_tap_tableset.xml
      * projects/theory/snap/simtap/PDR143/tap/PDR143-2_votable.xml

   * We have a few files larger than 5M bytes, most of them in the theory project.
      * projects/dm/vo-dml/libs/eclipselink.jar
      * projects/theory/snap/simtap/PDR143/PDR143-2.vo-urp
      * projects/theory/snap/simtap/PDR143/html/PDR143-2.html
      * projects/theory/snap/simtap/PDR143/tap/PDR143-2_tap_tableset.xml
      * projects/theory/snap/simtap/PDR143/tap/postgres/PDR143-2_create_tap_schema.sql
      * projects/theory/snap/simtap/PDR143/tap/mssqlserver/PDR143-2_create_tap_schema.sql
      * projects/theory/snap/simtap/PDR143/tap/PDR143-2_votable.xml
      * projects/theory/snap/simtap/PDR143/tap/PDR143-2_vodataservice.xml
      * projects/theory/snapdm/input/other/sourceDM/IVOACatalogueDataModel.pdf

   * We have 70 files larger than 1M bytes.

   * Everything else is smaller than 1M byte.

Note that many of our largest files are 10Mbyte+ =html= and =xml= files,
presumably generated by our modelling tools.
Equally, some of our smallest files are =html= and =xml= files, and we would not
want any of the =html= and =xml= source files for our standards documents
to be stored externally as binary files.

---+ Project types

Looking at the current contents volute, we have four different project types.

---++ Theory projects
 
It looks like the three theory projects contain a relativley small number
of human edited source files, and the majority of the space is taken up by
machine generated files.

   * projects/theory - 220M
      * snap - 108M
      * snapdm - 109M
      * simdal - 3.3M

There is a good case for exporting each of the three theory projects as
separate !GitHub repositories.

Even without using the LFS extension to manage the larger files, these
projects would all be under the recomended 1Gbyte per repository limit.

---++ Data models

Four of the data model projects are directly related to the standard
documents defining the corresponding data model.

   * projects/dm
      * CubeDM-1.0 - 8.1M
      * ImageDM - 3.6M
      * provenance - 5.8M
      * SpectralDM-2.0 - 7.3M

The majority of the space is taken up by a mixture of medium sized (1M <
s < 10M) =doc=, =pdf= and =png= files.

The fith data model project is for the VO Data Modelling Language, VO-DML.

This project accounts for over 100M of the 126M of space used by the data
model projects, and is the third largest project in the volute repository.

   * projects/dm - 126M
      * ....
      * vo-dml - 101M

Again, the majority of the space is taken up by a mixture of medium sized
(1M < s < 10M) =doc=, =pdf= and =png= files.

Although this project is related to the VO-DML and UTYPE specifications,
there is a case for exporting it as a separate separate !GitHub repository.

In addition to the documents for the VO-DML and UTYPE specifications the
vo-dml project also contains definitions of the models themselves along with
the source code for the tools for validating the models and for building
derived data products from them.

---++ VOSpace service

We have one project that contains code for a program, donated by Rick Wagner
at UC San Diego.

   * projects/grid/vospace/php_endpoint
      * size : 1.5M
      * type : PHP web service
      * lang : php

<verbatim>
    = PHP VOSpace Endpoint =

    VOSpace endpoint building on top of the [http://www.irods.org iRODS] client, Prods.

    Requires Prods, which is part of the iRODS distributions (under clients). Also uses
    [http://simpletest.sf.net SimpleTest] for unit tests. Configure the locations in config.inc.


    Rick Wagner
    http://lca.ucsd.edu/projects/rpwagner
    rwagner@physics.ucsd.edu
</verbatim>

As a self-contained source code project there is a case good case for
exporting this project as separate !GitHub repository of its own.

---++ Vocabularies

The vocabularies project contains the build tree for the IVOA vocabulary
SKOS files.

Although this project is relatively small, 3.4M, it is not directly related
to an IVOA document or standard.

As a self-contained source code project there is a case good case for
exporting this project as separate !GitHub repository of its own.

---++ Documents and standards

Everything else in our repository are either source text for our documents
or tools for creating documents.

If we wanted to we could use the LFS extension to process all of the
=doc=, =pdf= and =jpeg= files separately.
However, this would not reduce the size of a local clone of the repository,
nor the time it would take to download it.

---+ Proposed structure

If we take a copy of the exported snapshot and split out the projects
identified above as candidates for separate !GitHub repositories.

<verbatim>
    mkdir github-repos
    pushd github-repos

        cp -r ../volute-export local-temp

        mv local-temp/projects/theory         ivoa-theory
        mv local-temp/projects/dm/vo-dml      ivoa-dml
        mv local-temp/projects/vocabularies   ivoa-vocabularies
        mv local-temp/projects/grid/vospace/php_endpoint php-vospace
        mv local-temp/projects ivoa-documents

    popd

    du -h github-repos > github-repos.txt

</verbatim>

The we get the following set of candidate !GitHub repositories:

   * github-repos - 391M
      * php-vospace - 1.5M
      * ivoa-vocabularies - 3.4M
      * ivoa-documents - 66M
      * ivoa-dml - 101M
      * ivoa-theory - 220M

If we split the three theory projects into separate !GitHub repositories,
then we get the following:

   * github-repos - 391M
      * php-vospace - 1.5M
      * ivoa-vocabularies - 3.4M
      * ivoa-documents - 66M
      * ivoa-dml - 101M
      * ivoa-snap - 108M
      * ivoa-snapdm - 109M
      * ivoa-simdal - 3.3M

---+ Historical documents

It would be possible to further reduce the size of the ivoa-documents !GitHub repository
by excluding the historical versions of the documents stored in the current repository.

---+ References

   * [[http://google-opensource.blogspot.co.uk/2015/03/farewell-to-google-code.html][Farewell to google code]]
   * [[https://code.google.com/export-to-github/][GitHubExporter]]
   * [[https://code.google.com/p/support-tools/wiki/GitHubExporterFAQ][GitHubExporter FAQ]]
   * [[https://code.google.com/p/support/wiki/ReadOnlyTransition][ReadOnly transition]]

   * [[https://git-lfs.github.com/][Git Large File Storage]]
   * [[https://github.com/github/git-lfs/blob/master/docs/spec.md][Git LFS Specification]]
Topic revision: r4 - 2015-07-31 - DaveMorris
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