Calibre 9 and Box Cloud Storage - Page 3

Sirtel · 02-01-2026, 06:42 AM

Quote:

Originally Posted by dizzy274

Sorry to be obtuse here. I really can't see the difference between having the Calibre Library on ( say ) an external drive and using Box, it's just a longer piece of string.
Ian.

There is a difference. I'm not an IT person, but it has been explained here several times. And the overall consensus is: don't do it. A calibre library must be local (a connected external drive counts as local while it is connected; a cloud drive with online-only files doesn't).

JSWolf · 02-01-2026, 06:47 AM

Quote:

Originally Posted by dizzy274

Hi Jon,

Box can't do a two way sync as it has nothing to sync to, I don't have a copy of my library on any local drive, if I did you'd be right, probably. You're not thinking of the late unlamented Box Sync are you?

Ian.

Ian.

If you are not using Box cloud storage, then what are you using and how are you using it?

Sirtel · 02-01-2026, 07:00 AM

The problem here is not two-way sync. The first issue is that two programs are accessing the calibre database at the same time - calibre itself and Box (which is syncing the changes to the cloud in the background). That's already pretty risky. The second issue is online-only files. Calibre is designed to work with local files; any changes to the database must happen without latency or delays, or again you'll risk corrupting your library. There is always some latency with online-only files.

JSWolf · 02-01-2026, 07:20 AM

Quote:

Originally Posted by Sirtel

The problem here is not two-way sync. The first issue is that two programs are accessing the calibre database at the same time - calibre itself and Box (which is syncing the changes to the cloud in the background). That's already pretty risky. The second issue is online-only files. Calibre is designed to work with local files; any changes to the database must happen without latency or delays, or again you'll risk corrupting your library. There is always some latency with online-only files.

We'll know more when my questions get answered.

dizzy274 · 02-01-2026, 07:29 AM

but there's always some latency between you taking an action and it being registered on your local or remote disk. Windows is syncing changes to drives, it is just bright enough to single thread what you're doing, so is Box.

Ian.

Sirtel · 02-01-2026, 07:32 AM

Quote:

Originally Posted by dizzy274

but there's always some latency between you taking an action and it being registered on your local or remote disk. Windows is syncing changes to drives, it is just bright enough to single thread what you're doing, so is Box.

Ian.

Latency with online-only files is always bigger than with local files.

DNSB · 02-01-2026, 05:32 PM

There is still a chance of your library database being corrupted when connecting to it over a network connection which has very different characteristics to a local USB connection. I prefer to avoid that possibility but other people have different risk tolerances. As mentioned before, many of the complaints include comments such as "I've been doing this for years without a problem". Several of those complaints were from people who were storing their libraries on a NAS appliance on their local network.

Out of curiosity, where do you back up your calibre library to? A different location on Box? My personal backup strategy involves 2 cloud based storage providers and a grandfather/father/son trio of local removable storage devices. As the old saw goes, I know I am paranoid, I just don't know if I am paranoid enough.

theducks · 02-01-2026, 10:57 PM

Quote:

Originally Posted by dizzy274

Sorry to be obtuse here. I really can't see the difference between having the Calibre Library on ( say ) an external drive and using Box, it's just a longer piece of string.

Ian.

The delays of any network can change the order things happen. Calibre has Data, indexes as well as 1 or more files associated with a single title.
A simple data error may cause a retry, while the entry in other files has already been updated

A local attached (internal or External) does not introduce random delays.

dizzy274 · Yesterday, 10:38 AM

Hi Again,

I had intended to knock this thread on its head as it's obvious we're not going to agree then I saw a post from "theducks", a blast from my old Calibre Companion days!

I've mentioned my backup strategy a couple of times, but again... and remember all this is single threaded, there is only one user or program or application at work at any one time - I use Box for my main Calibre Library, when I've finished doing what ever I want to this library, I run MegaSync on my PC to sync it with a Mega copy of the Calibre Library. At Midnight MegaSync runs on one of my tablets and syncs that copy of the Calibre Library to that tablet. No I don't back it up ( sync it ) to another copy on Box although that would be ok, it's not like having the original and the backup on the same disc, I just have other reasons for having a Mega copy and I haven't got enough free space on Box, and no I don't update or otherwise manipulate the Mega copy.

theducks - yes I sort of agree, but millions of people use cloud storage for much more complex applications than Calibre, I'm willing to trust that they can handle the retries and whatever.

More basically I want to do what I'm doing and I want to make it work, after all it's only a few thousand books and I'll almost certainly be able to recover them even if in the direst of circumstances it would take me a day or two. I might have to re-think when I exceed my Box free quota, but that's another challenge.

Best Regards.
Ian.

Sirtel · Yesterday, 11:59 AM

You can still have a cloud backup in a completely safe way. Keep your active library on a local drive, not connected to any cloud. After you've finished working and closed calibre, run FreeFileSync in mirror mode between your local library and a backup copy on a cloud drive (it's very fast, because only the changed files are updated, not the entire library). Done. No danger of corruption or messing up your library.

Of course, if you want to live dangerously with a live online-only cloud library, that's your business. Just be aware of the risks and that such an approach is not approved by calibre developers.

Sirtel · Yesterday, 12:02 PM

Quote:

Originally Posted by dizzy274

and remember all this is single threaded, there is only one user or program or application at work at any one time...

That's not true from your description. You have two applications working at the same time - Box and calibre.

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02-01-2026, 07:00 AM	#33
Sirtel Grand Sorcerer Posts: 14,617 Karma: 245020905 Join Date: Jan 2014 Location: Estonia Device: Kobo Sage & Libra 2	The problem here is not two-way sync. The first issue is that two programs are accessing the calibre database at the same time - calibre itself and Box (which is syncing the changes to the cloud in the background). That's already pretty risky. The second issue is online-only files. Calibre is designed to work with local files; any changes to the database must happen without latency or delays, or again you'll risk corrupting your library. There is always some latency with online-only files.

02-01-2026, 07:29 AM	#35
dizzy274 Member Posts: 18 Karma: 52648 Join Date: Jan 2013 Device: Nexus 7	but there's always some latency between you taking an action and it being registered on your local or remote disk. Windows is syncing changes to drives, it is just bright enough to single thread what you're doing, so is Box. Ian.

02-01-2026, 05:32 PM	#37
DNSB Bibliophagist Posts: 50,011 Karma: 178398936 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	There is still a chance of your library database being corrupted when connecting to it over a network connection which has very different characteristics to a local USB connection. I prefer to avoid that possibility but other people have different risk tolerances. As mentioned before, many of the complaints include comments such as "I've been doing this for years without a problem". Several of those complaints were from people who were storing their libraries on a NAS appliance on their local network. Out of curiosity, where do you back up your calibre library to? A different location on Box? My personal backup strategy involves 2 cloud based storage providers and a grandfather/father/son trio of local removable storage devices. As the old saw goes, I know I am paranoid, I just don't know if I am paranoid enough.

Yesterday, 10:38 AM	#39
dizzy274 Member Posts: 18 Karma: 52648 Join Date: Jan 2013 Device: Nexus 7	Hi Again, I had intended to knock this thread on its head as it's obvious we're not going to agree then I saw a post from "theducks", a blast from my old Calibre Companion days! I've mentioned my backup strategy a couple of times, but again... and remember all this is single threaded, there is only one user or program or application at work at any one time - I use Box for my main Calibre Library, when I've finished doing what ever I want to this library, I run MegaSync on my PC to sync it with a Mega copy of the Calibre Library. At Midnight MegaSync runs on one of my tablets and syncs that copy of the Calibre Library to that tablet. No I don't back it up ( sync it ) to another copy on Box although that would be ok, it's not like having the original and the backup on the same disc, I just have other reasons for having a Mega copy and I haven't got enough free space on Box, and no I don't update or otherwise manipulate the Mega copy. theducks - yes I sort of agree, but millions of people use cloud storage for much more complex applications than Calibre, I'm willing to trust that they can handle the retries and whatever. More basically I want to do what I'm doing and I want to make it work, after all it's only a few thousand books and I'll almost certainly be able to recover them even if in the direst of circumstances it would take me a day or two. I might have to re-think when I exceed my Box free quota, but that's another challenge. Best Regards. Ian.

Yesterday, 11:59 AM	#40
Sirtel Grand Sorcerer Posts: 14,617 Karma: 245020905 Join Date: Jan 2014 Location: Estonia Device: Kobo Sage & Libra 2	You can still have a cloud backup in a completely safe way. Keep your active library on a local drive, not connected to any cloud. After you've finished working and closed calibre, run FreeFileSync in mirror mode between your local library and a backup copy on a cloud drive (it's very fast, because only the changed files are updated, not the entire library). Done. No danger of corruption or messing up your library. Of course, if you want to live dangerously with a live online-only cloud library, that's your business. Just be aware of the risks and that such an approach is not approved by calibre developers.

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