Questions on calibre migration

[DrChiper]

Hi Kovid, on migration to another computer I used the Export/Import function, which works in principle very well
I really liked it to find all my settings and saved searches.

However (there is always an however ) I encountered some points I like to have clarified.

1. On export, I choose the top directory of an empty USB-drive.
   Calibre refused to use it as it was not regarded as an empty folder. Creating on the USB-drive some empty folder solved that, but it might confuse the average user.
2. On import, calibre correctly informed me the saved directory structure, but refused to restore them. Only when I manually made these directories in the destination drive/folder, all calibre directories were restored. It should be more straightforward that calibre suggests to create those known original directories, unless the user decides otherwise. Again it might confuse the average user.
3. After restoring, I noticed a difference in the shown library structure (see attachments: left original, right migrated). The migrated libraries now show also the library path, while curiously also the same libraries without path are shown. My question: is this correctable?

I used calibre 3.30 32bits (source) and calibre 3.30 64bits (target).

[DrChiper]

Ok, I could find no way to fix this via calibre: at least I could not find it.
So this is what I did:

1. In calibre, I deleted all libraries but kept the files, and closed calibre.
2. In Windows, I renamed the top directory name of those still present libraries with according files, by adding some name, say "ORG".
3. I opened calibre and created all libraries anew with the original intended names: no more path-name prefixes in the library names! I closed calibre.
4. In Windows, I deleted the contents of the just created libraries, and copied the contents of the previously renamed "ORG" directories into them.
5. I started calibre and all libraries with their contents could now be found using the single library name.
6. For every library, I issued the Library Maintenance->Library check to make sure the libraries were healthy.
7. I closed calibre and removed the "ORG" directories.
8. Job done.

Summarizing,

• the import worked to init the new calibre installation with plugins, saved searches, etc. from my original calibre on the old computer;
• the import does not worked to define the libraries in the new calibre installation in the same manner as they were on the old computer (duplicates, additional path names);
• however, with some tweaking this can be corrected;
• also the export from calibre on the old computer does not seem to include file metadata.opf; perhaps not needed?

I'm not sure whether this behavior is due to my handling, or some oversight, or that this is erroneous behavior of calibre.
Anyone?

[Sirtel]

I've never used the import-export function, and I've moved my libraries to new computers at least three times. I always copy my libraries and the configuration folder manually to an external HD and from there to a new computer. Works like a charm. Nothing has ever been lost, all the plugins, settings, preferences have always been intact.

[BetterRed]

I've used the export/import feature without any issues. In two instances between different operating systems, Windows->MacOS, and Linux Mint->Windows, the other two were Windows->Windows. I've also provided guidance to a couple of people over the phone when they needed to use it, again with no issues.

BR

[kovidgoyal]

Import does not re-create the full path to previous libraries, it only preserves the library name. This is because there is no guarantee that the full path is valid on the new computer. You can always rename the libraries/move them manually after import if needed. The important thing is that *all* the data is preserved.

I'm not sure how you ended up with paths as library names, but I cannot reproduce that.

[DrChiper]

Well, the problem is that not many persons probably do use the migration functions export/import much, so it is not tested that much.

Further, I used calibre a long time on my old and trusty machine, starting with version 1.x or so. During all those years derelict and obsolete files seem to clutter the calibre environment as I noticed when inspecting and comparing old and new directories. So a fresh new start from time to time is never a bad thing IMHO.

Originally Posted by kovidgoyal

Import does not re-create the full path to previous libraries, it only preserves the library name. This is because there is no guarantee that the full path is valid on the new computer.

Agree. Only on importing, the original full path-name with library name were shown (hence known), plus an input field so you could define the new destination. So I guess somehow the original path is remembered after all.

Originally Posted by kovidgoyal

The important thing is that *all* the data is preserved.

I did a compare between the original directories and the new ones and noticed that all files are present on the new computer, minus file "metadata.opf". The latter was missing for all entries. No idea whether that file is important, can be recreated or is now obsolete.

Originally Posted by kovidgoyal

I'm not sure how you ended up with paths as library names, but I cannot reproduce that.

In this case, by a rare coincident, the old source location and the new target destination *WHERE* the same, which *MIGHT* have helped to create the import confusion. Remember from my pictures: all libraries were shown with and without a path-name prefix, hence appeared twice.

At this moment calibre 64bits seems to work happily on the new ridiculous state-of-the-art machine using the old libraries. Even without those missing "metadata-opf" files.

[kovidgoyal]

metadata.opf is a backup file that is not needed for normal operation and it will be regenarated automatically over time in your new libraries.