mirrors/git-annex
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages 1 Wiki Activity Actions

sameas documentation

Browse source
This commit is contained in:
Joey Hess 2019-10-11 14:04:58 -04:00
parent 1b9c1d1737
commit c0e88b7695
No known key found for this signature in database
GPG key ID: DB12DB0FF05F8F38
1 changed files with 58 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

58
doc/tips/multiple_remotes_accessing_the_same_data_store.mdwn Normal file
View file

@ -0,0 +1,58 @@
A remote configures git-annex with a way to access a particular data
store. Sometimes, there's more than one way for git-annex to access the
same underlying data store. It then makes sense to have multiple remotes.
The most common and easy case of this is when the data store is itself a
git-annex repository. For example, using git-annex on your laptop, you
might add a ssh remote which works from anywhere. But, when you're located
on the same LAN as the server, it might be faster or simpler to use a
different ssh url.
git remote add server someserver.example.com:/data
git remote add lanserver someserver.lan:/data
git-annex is able to realize automatically that these two remotes both
access the same repository (by contacting the repository and looking up its
git-annex uuid). You can use git-annex to access which ever remote you
want to at a given time.
[[Special_remotes]] don't store data in a git-annex repository. It's
possible to configure two special remotes that access the same underlying
data store, at least in theory. Whether it will work depends on how the
two special remotes store their data. If they don't use the same filename
(or whatever), it might not work.
The case almost guaranteed to work is two special remotes of the same type,
and other configuration, but with different urls that point to the same
data store. For example, a [[special_remotes/git-lfs]] repository can be
accessed using http or ssh. So two git-lfs special remotes can be set up,
and both access the same data.
git annex initremote lfs-ssh type=git-lfs encryption=shared url=git@example.com:repo
git annex initremote --sameas=lfs-ssh lfs-http type=git-lfs url=https://example.com/repo
The `--sameas` parameter tells git-annex that the new special remote
uses the same data store as an existing special remote. Note that
the encryption= parameter, which is usually mandatory, is omitted.
The two necessarily encrypt data in the same way, so it will
inherit the encryption configuration. Other configuration is not inherited,
so if you need some parameter to initremote to make a special remote behave
a certian way, be sure to pass it to both.
Finally, it's sometimes possible to access the same data stored in two
special remotes with different types. One combination that works is
a [[special_remotes/directory]] special remote
and a [[special_remotes/rsync]] special remote.
git annex initremote dir type=directory encryption=none directory=/foo
git annex initremote --sameas=dir rsync type=rsync rsyncurl=localhost:/foo
If a combination does not work, git-annex will be unable to access files
in one remote or the other, it could get into a scrambled mess. So it's
best to test a a combination carefully before you start using it for real.
If you find combinations that work, please edit this page to list them.
## known working combinations
* directory and rsync