Using calibre on multiple computers

[PeterT]

Why not use the sleep command to wait for a predetermined time period rather than a while loop?

[ratinox]

Originally Posted by sheepdog

...
sleep 15
...

instead of your for loops.

Oh. PeterT made the same suggestion. Though there probably is (or should be) a better way to query the Dropbox software directly instead of waiting some arbitary time. You might also consider using rclone which is similar to rsync but for cloud storage services like Dropbox and OneDrive. I have used rclone for replication against OneDrive. It worked.

[JSWolf]

Originally Posted by Sirtel

I'm pretty sure those who want to do it are going to do it anyway.

But at least they've been warned if they read this thread.

[JSWolf]

Originally Posted by sheepdog

I certainly agree, that you cannot depend upon Dropbox alone, and you need to backup and check the libraries often. That said, here is a simple-minded script that works on my linux machine to do what was suggested:

deleted the code as I don't want to help anyone corrupt their library

Please make a new script that will use rsync to sync from your active library to your dropbox directory to be able to sync your library without risk of your active library becoming corrupt.

Also, please delete your existing script or others will use it and corrupt their library.

[ratinox]

Originally Posted by JSWolf

Please make a new script that will use rsync to sync from your active library to your dropbox directory to be able to sync your library without risk of your active library becoming corrupt.

rclone is the superior tool. It is designed specifically to work with cloud storage providers like Dropbox and OneDrive.

[sheepdog]

Yes, corrected script follows:

#!/bin/bash

dropbox start
dropbox status
echo -n "SYNCING CALIBRE"
wait_time=15
i=0
while [ $i -le $wait_time ]; do
	sleep 1
	echo -n .
	((i++))
done
dropbox stop
echo -n "STOPPING DROPBOX"
i=0
while [ $i -le $wait_time ]; do
	sleep 1
	echo -n .
	((i++))
done
calibre 
echo - n "SYNCING DROPBOX"
i=0
while [ $i -le $wait_time ]; do
	sleep 1
	echo -n .
	((i++))
done
dropbox start
dropbox status
i=0
while [ $i -le $wait_time ]; do
	sleep 1
	echo -n .
	((i++))
done
dropbox stop

The Dropbox does not appear to have a method for querying the sync state. So the script uses an arbitrary wait time.

[PeterT]

Umm.. why not replace

i=0
while [ $i -le $wait_time ]; do
	sleep 1
	echo -n .
	((i++))
done

by

sleep $wait_time

Sure you won't get a snazzy dot being displayed every second but....

[JSWolf]

Originally Posted by ratinox

rclone is the superior tool. It is designed specifically to work with cloud storage providers like Dropbox and OneDrive.

Does rclone do a one way sync to Dropbox and/or OneDrive?

[PeterT]

Originally Posted by JSWolf

Does rclone do a one way sync to Dropbox and/or OneDrive?

From the documentation

rclone sync
Make source and dest identical, modifying destination only.

and yes, it supports DropBox and OneDrive

[PeterT]

Originally Posted by ratinox

rclone is the superior tool. It is designed specifically to work with cloud storage providers like Dropbox and OneDrive.

Thanks for suggesting rclone. It's allowed me easy data backup from my pikapod app to local storage.

[sheepdog]

The key to using Dropbox with Calibre is to realize that, so long as Calibre and the Dropbox daemon are never running at the same time, the risk of corruption is no greater than with one or the other alone. That said, be aware that Calibre is still running even when the main window is closed if there is a viewer window open. I could not find an option in Calibre to close the viewer windows automatically whenever the main window is closed. So to use Dropbox you need to be sure to close all Calibre viewer windows and the main window before running the Dropbox daemon. I have scripted this condition in linux as well, for myself. The code will be very system dependent, so not including it here.

[BetterRed]

Originally Posted by sheepdog

The key to using Dropbox with Calibre is to realize that, so long as Calibre and the Dropbox daemon are never running at the same time, the risk of corruption is no greater than with one or the other alone. . . .
be aware that Calibre is still running even when the main window is closed if there is a viewer window open.

I could not find an option in Calibre to close the viewer windows automatically whenever the main window is closed.

FYI: The viewer and the editor run as separate processes, and they can open files directly - i.e not via the library manager and not necessarily within a calibre library.

I don't know of any easy way to determine if a folder (e.g. a calibre library) or it's contents are in use.

BR

[PeterT]

Originally Posted by BetterRed

I don't know of any easy way to determine if a folder (e.g. a calibre library) or it's contents are in use.

BR

Check out the SysInternals command handle; it might help --> https://learn.microsoft.com/en-ca/sy...wnloads/handle

[ratinox]

Originally Posted by PeterT

Check out the SysInternals command handle; it might help --> https://learn.microsoft.com/en-ca/sy...wnloads/handle

And the lsof command on Linux and some Unix.

[ratinox]

Originally Posted by sheepdog

The key to using Dropbox with Calibre is to realize that, so long as Calibre and the Dropbox daemon are never running at the same time, the risk of corruption is no greater than with one or the other alone.

This is not entirely accurate.

Leaving aside Dropbox in particular, the root problem is that multiple instances of an open database file on replicated or shared storage will result in corruption. Instance 1 writes, replication system replicates, but Instance 2 does not know that the file is changed so it writes and damages the file. This damage is replicated back to Instance 1's filesystem but Instance 1 does not know of these changes so it writes and causes further damage. The more times this happens, the more damage is done.

Dropbox in particular may have additional problems. I don't use it so I don't know. I do use Syncthing, being careful to avoid Calibre concurrency, and it has been fine for many years.