Backing up SVN to a Zip File

I promised in my post about getting a UTC Formatted Date and Time from the command line that I would give some tips about using it for backups.

I use my dateTimeUTC command line application I wrote about and 7-zip which is an open source command line zip utility.

First of all, I backup to my d drive into a directory (folder) called backups.

The command line tool SVNADMIN has a hotcopy option which makes a copy of the entire Repository to a new location without having to stop the SVN service.

So the first step I do is delete the COPY of the Repository (if it exists), then make a new copy if it.

IF EXIST "d:\backups\SVN\SVN_Repos" RMDIR /S /Q "d:\backups\SVN\SVN_Repos"
MKDIR "d:\backups\SVN\SVN_Repos"

SVNADMIN hotcopy D:\SVN_Repos D:\backups\SVN\SVN_Repos --clean-logs

We now have a complete copy of the repository in D:\backups\SVN\SVN_Repos.

Now, using my datetimeUTC tool, I set a variable to the value of the filename I want to use

for /f "usebackq" %%a in (`datetimeUTC.exe yyyyMMddTHHmmssZ`) do (set UTCdts=%%a%)

The variable %newfile% now contains something like “”

Just in case it exists, I attempt to delete this file

del d:\backups\SVN\%newfile%

I then compress the entire folder using 7-zip.

7z.exe a -mx=9 -tzip -r d:\backups\SVN\%newfile% d:\backups\SVN\SVN_Repos

Calling 7z by itself will give you the options, but the options I use are:
a : Add files to archive
-mx=9 : Use maximum compression (5 is default)
-tzip : Set type of archive to zip
-r : Recurse subdirectories

Then, at the end, delete the COPY of the SVN Repository

IF EXIST "d:\backups\SVN\SVN_Repos" RMDIR /S /Q "d:\backups\SVN\SVN_Repos"

You can test the zip file for errors using

7z.exe t d:\backups\SVN\%newfile%

Directly after the test command, the parameter %ERRORLEVEL% will return a non zero result if there was any error.

I’ll post another log soon on how to email logs from the command line when errors are detected. In the mean time, set up scheduled tasks to run a batch file do complete your backing up processes.

And remember the golden rule which goes something along the lines of “If you’ve never restored a backup, you may as well not have a backup”.

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