tasket
commented
5 days ago Hi @Eric678
The local path is not saved in the archive, its specified with the --local command line parameter which is required for most commands. It acts like an absolute base path (or path prefix) so you can restore multiple volumes at once, much like you can backup multiple vols at once. --local can also be added as a default setting to /etc/wyng/wyng.ini to avoid typing it repeatedly.
The --saveto option is for special cases when you need to restore to a very specific path and/or there is no suitable snapshot-capable storage setup on the local system. Only one vol may be restored at a time with --saveto.
wyng archive storage format uses a huge number of inodes. In my case backup drives are mkfs'd with a relatively small number,
That does seem like a special case but also worth a mention in the docs. FWIW, I've done some testing with Ext4, XFS and Btrfs and the only time it seemed to come near to causing inode exhaustion was when the archive chunk size was set to 64KB and the data was especially compressible (hence very small files) and no deduplication was used (dedup has an effect of conserving inodes, if there is substantial duplication). The two obvious ways out of this is doing mkfs with the default ratio of inodes or creating a new Wyng archive with larger chunk size; a third route is to enhance Wyng with an option that lets you set the maximum archive size.
does wyng send check that there are enough inodes when it is checking space in advance? If it runs out, does it fail atomically and roll back the whole session? Just the last part vol?
No, it doesn't do this. It could conceivably provide a warning when a limit is being approached, or warn anytime an fs doesn't have at least 1 inode per 16KB... but most archive utilities (like tar) which can extract large number of small files don't do this.
If it runs out, does it fail atomically and roll back the whole session? Just the last part vol?
It will fail atomically per volume, meaning you may have some volumes completed for a given session number, while the session doesn't exist for other volumes including the vol being backed up when the error occurred. There will also be (in that one archive volume) some unassociated data that will be deleted the next time Wyng runs.
Eric678
New user here, great work - sorely needed for Qubes, a couple of issues: There is no mention of receiving "other" volumes, question: is the path bundled into the archive or does every vol receive require a separate wyng command with --saveto? (Guessing yes, should be documented) How to format the json for this scenario? The other is I feel there should be a paragraph right up front describing the wyng archive storage format uses a huge number of inodes. In my case backup drives are mkfs'd with a relatively small number, has never been a issue. A single 10T offline backup drive's 1.2M inodes are wiped out by a 70GB wyng archive, which is not big, using the default chunk size of 128K. Does bring up another question, does wyng send check that there are enough inodes when it is checking space in advance? If it runs out, does it fail atomically and roll back the whole session? Just the last part vol? Thanks!