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Data Volume container: impossible to commit? Did I miss something?


(Spoon25) #1

Hello, I’m new to docker and just started playing with it in the last days. What I’m trying to do is setup images containing Oracle Database 12c and use the pluggable database feature to be able to “plug” or “unplug” a DB based on the apps I need to run against the DB container. So I wanted to use data volume container to provide an image to store only the DB data files, but it looks like I can’t commit changes (files) done by a container using the volume with the “–volumes-from” param.
Did I miss something? Or there is, for now, no way to commit changes in a data volume container done by containers “loading” the volumes?

Thanks a lot (and sorry if the question is not clear, I’m still trying to get used to docker wording)


(Sven Dowideit) #2

Heya,

yes, thats correct, volumes are stored in a non-layered fs, so that they have more straightforward performance characteristics.

I guess you could use images to backup volumes by making a backup-volume image which copies the volume files into itself - but that does get hairy if done live.


(Spoon25) #3

Thanks Sven,
It makes sense (also because I stopped jumping around between blog posts and I read the doc from A to Z now).
I like the idea of a “backup-volume” image, I will try to setup something going in that direction (and because to plug or unplug a database in Oracle 12c it require some SQL as well I guess the backup-volume image can become my “tools” image taking care of unplugging the database and doing the backup or restore from a backup and plug the db back).
Thanks a lot for your reply.