2016-11-12 Sofar, cloud backup is not a resounding success
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So the first few tries of a backup to a remote webdav filesystem using amanda have been done. The result is that the davfs2 filesystem driver is very I/O intensive when writing to the local cache. The fact that amanda creates 2 gigabyte files (actually compressed tar archives) also makes the caching of davfs2 use quite a high amount of diskspace. Eventually things get flushed to the remote filesystem and this fills the uplink completely. During this I/O intensive period certain things are very slow, for example the df command. The running webserver is still fast enough. It's easy to calculate that it takes a while at 20 megabit to upload a few gigabytes, but it seems clear that this needs a bit more work before I can replace the tape backups. There is also the interesting chicken and egg problem of how to restore from scratch.