Using calibre on multiple computers

[Marcy]

I use calibre on 2 different computers. I keep the library in my dropbox, so it should sync to each computer.

However, books added on one computer, while safely in dropbox, are not picked up in calibre on the other computer.

I found the "Check Library" option which shows all the books as "Extra Titles" but I see no easy way to add them to calibre without manually going and adding each one individually. The only option the Check Library offers me for these titles is to delete them, there is no option to add them to calibre.

Am I missing something that would make this easier?

[Sirtel]

Calibre is not meant for using on more than one device. Library corruption will result, as you've discovered.

Yes, the only option is to add the extra titles manually. That's because this is not supposed to be a regular occurrence, but an one-time mishap. If it happens regularly (as it always does when two-way cloud syncing is involved), then you're doing something you shouldn't (like using two-way cloud syncing).

[BetterRed]

@Marcy - see https://manual.calibre-ebook.com/faq...rked-drive-nas

Do not put your calibre library on a networked drive.

Services such as Dropbox, OneDrive, iDrive etc are regarded as network storage, they're OK for calibre library backup storage, but they're NOT OK for active calibre library storage.

BR

[DNSB]

To quote a too commonly posted item over the last 13 years:

If you keep your library on a networked drive (NAS, OneDrive, DropBox, whatever), it is not a question of if your library will be corrupted but when.

See I am getting errors with my calibre library on a networked drive/NAS? in the calibre FAQs and SQLite Over a Network, Caveats and Considerations for more information.

[JSWolf]

Keep your calibre library away from cloud storage forever. No cloud storage has a one-way sync. They are all two-way. Because of this, your library WILL become corrupt and in some cases, unfixably corrupt.

[JSWolf]

Originally Posted by BetterRed

@Marcy - see https://manual.calibre-ebook.com/faq...rked-drive-nas



Services such as Dropbox, OneDrive, iDrive etc are regarded as network storage, they're OK for calibre library backup storage, but they're NOT OK for active calibre library storage.

BR

Bad idea. You have to make a backup in order to allow the cloud storage access to your library and since you already have to make a backup, may as well just go with that backup as once you let the cloud storage access to the backup, it's most likely a goner.

[slm]

For what it may be worth: I have been using Calibre since its first version. All that time, the library has been in a folder that Dropbox backs up. For a while, I ran Calibre on two computers and had all the problems others have mentioned. But once I stopped running a second copy of Calibre many, many years ago (and stopped making changes to the relevant folder outside of Calibre)I have had no problems.

YMMV.

On the plus side, I have changed computers at least six times over the years and just installing Calibre and pointing it to the library folder worked fine each time.

[Sirtel]

Originally Posted by JSWolf

Bad idea. You have to make a backup in order to allow the cloud storage access to your library and since you already have to make a backup, may as well just go with that backup as once you let the cloud storage access to the backup, it's most likely a goner.

No, it isn't. Keeping a back-up in Dropbox is perfectly fine. As long as it is a back-up and not a second active library.

[Sirtel]

Originally Posted by JSWolf

Keep your calibre library away from cloud storage forever. No cloud storage has a one-way sync. They are all two-way. Because of this, your library WILL become corrupt and in some cases, unfixably corrupt.

It's one-way sync if you use FreeFileSync to mirror your active library to Dropbox for backup.

[sheepdog]

It seems to me that it should be safe to use Dropbox, if you stick to the following regimen faithfully.

1. do not use Dropbox for anything other than the Calibre library,
2. turn off (or pause) automatic syncing of Dropbox on all computers,
3. before opening Calibre turn on Dropbox syncing only on the computer using Calibre and turn off Dropbox syncing before opening Calibre, This will sync down any changes made on another device.
4. do not open Calibre on multiple computers simultaneously, so only open Calibre while using it and close it (thereby syncing to the database) when finished,
5. when Calibre is closed, turn on Dropbox syncing and turn it off again when complete. This will prepare the updates to all other devices.

Obviously, this will only work if only one person is ever using the Calibre library and it is a little tedious, but could probably be easily scripted.

[JSWolf]

Originally Posted by sheepdog

It seems to me that it should be safe to use Dropbox, if you stick to the following regimen faithfully.

1. do not use Dropbox for anything other than the Calibre library,
2. turn off (or pause) automatic syncing of Dropbox on all computers,
3. before opening Calibre turn on Dropbox syncing only on the computer using Calibre and turn off Dropbox syncing before opening Calibre, This will sync down any changes made on another device.
4. do not open Calibre on multiple computers simultaneously, so only open Calibre while using it and close it (thereby syncing to the database) when finished,
5. when Calibre is closed, turn on Dropbox syncing and turn it off again when complete. This will prepare the updates to all other devices.

Obviously, this will only work if only one person is ever using the Calibre library and it is a little tedious, but could probably be easily scripted.

1. NO! You should never use the Dropbox sync software on your libraries. Use FreeFileSync to copy your libraries to the Dropbox directory and then let the sync software do it's thing. That way if something becomes corrupted, you won't lose your existing library.
2. Do not ever let the sync software touch your active libraries.
3. See #2.
4. If your Dropbox backed up library does become corrupted, you'll be syncing the corruption back to your active library.
5. See #2

You do not want to use the library from Dropbox unless you actually need to and only after you've verified that it's not corrupted or you've fixed it if it is corrupted. It's not a question of if your libraries will be corrupted, but of when.

[Sirtel]

Originally Posted by sheepdog

It seems to me that it should be safe to use Dropbox, if you stick to the following regimen faithfully.

1. do not use Dropbox for anything other than the Calibre library,
2. turn off (or pause) automatic syncing of Dropbox on all computers,
3. before opening Calibre turn on Dropbox syncing only on the computer using Calibre and turn off Dropbox syncing before opening Calibre, This will sync down any changes made on another device.
4. do not open Calibre on multiple computers simultaneously, so only open Calibre while using it and close it (thereby syncing to the database) when finished,
5. when Calibre is closed, turn on Dropbox syncing and turn it off again when complete. This will prepare the updates to all other devices.

Obviously, this will only work if only one person is ever using the Calibre library and it is a little tedious, but could probably be easily scripted.

1. is not necessary - of course you can use Dropbox for other things. You just can't have it running in the background all the time.

Also, be prepared to run the library check regularly, and I mean the extended version checking if the files are in sync with the database, not only the initial check.

[JSWolf]

Originally Posted by Sirtel

1. is not necessary - of course you can use Dropbox for other things. You just can't have it running in the background all the time.

Also, be prepared to run the library check regularly, and I mean the extended version checking if the files are in sync with the database, not only the initial check.

Just go by the answers I gave that says don't do it.

[Sirtel]

Originally Posted by JSWolf

Just go by the answers I gave that says don't do it.

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

[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:

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