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Diffstat (limited to 'doc/walkthrough.mdwn')
| -rw-r--r-- | doc/walkthrough.mdwn | 35 |
1 files changed, 23 insertions, 12 deletions
diff --git a/doc/walkthrough.mdwn b/doc/walkthrough.mdwn index 47f05ebcf..d2231c81e 100644 --- a/doc/walkthrough.mdwn +++ b/doc/walkthrough.mdwn @@ -277,25 +277,32 @@ add something like this to `.gitattributes`: * annex.backend=SHA1 -## migrating between backends +## migrating data to a new backend -Perhaps you had been using the WORM backend, but now have configured -git-annex to use SHA1 for new files. Your old files are still in WORM. How -to migrate that content? A quick and dirty way is to use the unannex -subcommand, which removes a file from git-annex's control, followed by -a re-add of the file, to put it in the new backend. +Maybe you started out using the WORM backend, and have now configured +git-annex to use SHA1. But files you added to the annex before still +use the WORM backend. There is a simple command that can migrate that +data: - # git annex unannex my_cool_big_file - unannex my_cool_big_file ok - # git annex add my_cool_big_file - add my_cool_big_file (checksum ...) ok + # git annex migrate my_cool_big_file + migrate my_cool_big_file (checksum...) ok + +You can only migrate files whose content is currently available. Other +files will be skipped. + +After migrating a file to a new backend, the old content in the old backend +will still be present. That is necessary because multiple files +can point to the same content. The `git annex unused` sucommand can be +used to clear up that detritus later. Note that hard links are used, +to avoid wasting disk space. ## unused data It's possible for data to accumulate in the annex that no files point to -nymore. One way it can happen is if you `git rm` a file without +anymore. One way it can happen is if you `git rm` a file without first calling `git annex drop`. And, when you modify an annexed file, the old -content of the file remains in the annex. +content of the file remains in the annex. Another way is when migrating +between backends. This might be historical data you want to preserve, so git-annex defaults to preserving it. So from time to time, you may want to check for such data and @@ -318,6 +325,10 @@ data anymore, you can easily remove it: # git annex dropunused 1 dropunused 1 ok +Hint: To drop a lot of unused data, use a command like this: + + # git annex dropunused `seq 1 1000` + ## fsck: verifying your data You can use the fsck subcommand to check for problems in your data. |