Calibre on a NAS Server (Synology DS920+) in 2021

Inukami · 09-03-2021, 11:39 AM

Hi All,

I’m wondering if it is still recommended not to put a calibre library on a NAS Server (Synology)? Or if there is a way to do this safely...

In past posts and on the calibre FAQ it still says ‘Do not put your calibre library on a networked drive’ where it recommended not to put calibre on a networked drive.

The posts are from a while ago so thought I would start a new discussion. Hardware and software has changed so wondering if recommendation has changed?

MobileRead

Calibre on a NAS Server (2019)
Advise on Calibre installation on NAS (synology 415+) (2017)

Reddit

There appears to be TWO ways in which you could access a calibre library from a NAS

Install Calibre on your sinology NAS using Docker (May 2021) by Marius Bogdan Lixandru (if your NAS can do this which mine can)
Install files and database on NAS and use calibre from computer to access books

I currently have one of my libraries installed using option 2 (as a sort of test) and I can access it from my Mac mini and my laptop (or any computer with calibre installed and access to the NAS). It's really useful obviously to use NAS as I can access wherever in the house and in particular one of my libraries is very large (manga library) so don’t want to put on computer.

Is it still recommended not to access calibre library from a NAS? If so, why not? For those who tried and it didn't work, what did it do? Corrupt files etc...?

If it is okay, which is best configuration (option 1 or 2 mentioned above or some other option)? And if you are using NAS, what do you do for backups / how do you do backups? Other things to make it safe to use?

Greatly appreciate any advice.

Thanks

Inukami

kovidgoyal · 09-03-2021, 12:38 PM

Nothing has changed, you still risk data loss putting your calibre library on a NAS. The way to do this safely is to run the calibre content server ona central machine and connect to it from other computers.

Inukami · 09-10-2021, 01:30 AM

Thanks @kovid for your response.

When you say run calibre content server on central machine and connect from other computers, do you mean connect on the browser or is there a way to open the database/books in the calibre software? The content server on browser is not ideal for me for editing etc...and would prefer to do it from the software on the laptop (if for example main library on mac mini). But if running content server on one computer, you can't access that database on another computer running calibre can you? Only via the browser?

Could you also access the database through two macs network locations (not the NAS)? Would this be using the Connect to folder feature? Or would this not work?

Thanks,

Inukami

kovidgoyal · 09-10-2021, 02:00 AM

via the browser, there is no support for using a networked backend with the main calibre program. If you want to do that, then maintain your library on one main computer and use rsync or similar to copy the library from there to your server. The copy needs to be one way.

Inukami · 09-10-2021, 02:12 AM

Thanks Kovid.

Inukami

BrightSquirrel · 09-12-2021, 07:26 PM

I do not know if this is recommended, and your mileage may vary, and this might not help, but I have a NextCloud server and use that to sync between it and my computer. I Calibre pointed at the library that is synced on the local computer.

Never had an issue or any data loss. Been doing this for a couple of years now.

CubGeek · 09-17-2021, 11:25 AM

Quote:

Originally Posted by kovidgoyal

Nothing has changed, you still risk data loss putting your calibre library on a NAS. The way to do this safely is to run the calibre content server ona central machine and connect to it from other computers.

Would mind expanding on this answer, please? I (and I suspect others) have a NAS that's in a RAID specifically to prevent data loss. Thanks!

theducks · 09-17-2021, 01:03 PM

Quote:

Originally Posted by CubGeek

Would mind expanding on this answer, please? I (and I suspect others) have a NAS that's in a RAID specifically to prevent data loss. Thanks!

We are not talking corruption at the filesystem level (what RAID fights).

Calibre does many file and database entries that MUST remain in lockstep.
Also 2 simultaneous users might cause a clash as the write is from a memory version (and the other has no way of knowing things changed).
Calibre is not a true Client - server app. There are no File - record lock type interactions.

CubGeek · 09-17-2021, 02:09 PM

Quote:

Originally Posted by theducks

We are not talking corruption at the filesystem level (what RAID fights).

Calibre does many file and database entries that MUST remain in lockstep.
Also 2 simultaneous users might cause a clash as the write is from a memory version (and the other has no way of knowing things changed).
Calibre is not a true Client - server app. There are no File - record lock type interactions.

Ah, it's not a true server/client. That helps to make more sense. Thankyou for the clarification!

Appreciate it.

kovidgoyal · 09-17-2021, 11:13 PM

Quote:

Originally Posted by CubGeek

Would mind expanding on this answer, please? I (and I suspect others) have a NAS that's in a RAID specifically to prevent data loss. Thanks!

There's nothing to expand, network filesystems are all broken, they break various integrity guarantees that calibre makes use of for efficient file operations. So keeping the library on a network filesystem will eventually lead to data loss, because of bugs in the network filesystem drivers. Use the calibre content server if you want true networked access.

Networked filesystem basically work only if you restrict yourself to simple file copy operations and nothing else. calibre does much more than that.

CubGeek · 09-18-2021, 01:46 AM

Quote:

Originally Posted by kovidgoyal

There's nothing to expand, network filesystems are all broken, they break various integrity guarantees that calibre makes use of for efficient file operations. So keeping the library on a network filesystem will eventually lead to data loss, because of bugs in the network filesystem drivers. Use the calibre content server if you want true networked access.

Networked filesystem basically work only if you restrict yourself to simple file copy operations and nothing else. calibre does much more than that.

No need to be snippy when someone politely asks you for more information. Especially when the reasoning for such a sweeping statement wasn't part of your initial posting.

As for your suggestion, I have been working on setting up calibre-server on a headless server. So, thanks for that. Unfortunately, through no fault of yours, I'm sure, the arm64 repos are out-of-date (as we discussed in the recent thread about calibredb throwing a python error).

And, even with current a version running on an x64 Windows 10 system I can't make it do what I want, so I'm left weighing how much time and effort will be needed to learn how to make the software do what I want (or if it's even possible at all).

So, again, thanks for your efforts in creating the software. Even if I don't end up using it, it's definitely a powerful piece of coding.

09-03-2021, 11:39 AM	#1
Inukami Zealot Posts: 145 Karma: 12 Join Date: Jun 2017 Location: Australia Device: Mac Pro 2013 & Mini 2018, iPad Mini 4, iPhone 11, iBooks, K4Mac/PC	Calibre on a NAS Server (Synology DS920+) in 2021 Hi All, I’m wondering if it is still recommended not to put a calibre library on a NAS Server (Synology)? Or if there is a way to do this safely... In past posts and on the calibre FAQ it still says ‘Do not put your calibre library on a networked drive’ where it recommended not to put calibre on a networked drive. The posts are from a while ago so thought I would start a new discussion. Hardware and software has changed so wondering if recommendation has changed? MobileRead Calibre on a NAS Server (2019) Advise on Calibre installation on NAS (synology 415+) (2017) Reddit Synology NAS hosting Calibre database - help needed Do anyone have calibre server package for synology? Folks who use their Synology to serve up ebooks and comics, tell me all about your setup. I have a ton of files, but no good workflow Calibre-web installation on a NAS (help on how to do it) There appears to be TWO ways in which you could access a calibre library from a NAS Install Calibre on your sinology NAS using Docker (May 2021) by Marius Bogdan Lixandru (if your NAS can do this which mine can) Install files and database on NAS and use calibre from computer to access books I currently have one of my libraries installed using option 2 (as a sort of test) and I can access it from my Mac mini and my laptop (or any computer with calibre installed and access to the NAS). It's really useful obviously to use NAS as I can access wherever in the house and in particular one of my libraries is very large (manga library) so don’t want to put on computer. Is it still recommended not to access calibre library from a NAS? If so, why not? For those who tried and it didn't work, what did it do? Corrupt files etc...? If it is okay, which is best configuration (option 1 or 2 mentioned above or some other option)? And if you are using NAS, what do you do for backups / how do you do backups? Other things to make it safe to use? Greatly appreciate any advice. Thanks Inukami

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09-03-2021, 12:38 PM	#2
kovidgoyal creator of calibre Posts: 43,871 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Nothing has changed, you still risk data loss putting your calibre library on a NAS. The way to do this safely is to run the calibre content server ona central machine and connect to it from other computers.

09-10-2021, 01:30 AM	#3
Inukami Zealot Posts: 145 Karma: 12 Join Date: Jun 2017 Location: Australia Device: Mac Pro 2013 & Mini 2018, iPad Mini 4, iPhone 11, iBooks, K4Mac/PC	Thanks @kovid for your response. When you say run calibre content server on central machine and connect from other computers, do you mean connect on the browser or is there a way to open the database/books in the calibre software? The content server on browser is not ideal for me for editing etc...and would prefer to do it from the software on the laptop (if for example main library on mac mini). But if running content server on one computer, you can't access that database on another computer running calibre can you? Only via the browser? Could you also access the database through two macs network locations (not the NAS)? Would this be using the Connect to folder feature? Or would this not work? Thanks, Inukami

09-10-2021, 02:00 AM	#4
kovidgoyal creator of calibre Posts: 43,871 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	via the browser, there is no support for using a networked backend with the main calibre program. If you want to do that, then maintain your library on one main computer and use rsync or similar to copy the library from there to your server. The copy needs to be one way.

09-10-2021, 02:12 AM	#5
Inukami Zealot Posts: 145 Karma: 12 Join Date: Jun 2017 Location: Australia Device: Mac Pro 2013 & Mini 2018, iPad Mini 4, iPhone 11, iBooks, K4Mac/PC	Thanks Kovid. Inukami

09-12-2021, 07:26 PM	#6
BrightSquirrel Junior Member Posts: 9 Karma: 10 Join Date: Sep 2021 Device: Kindle Oasis	I do not know if this is recommended, and your mileage may vary, and this might not help, but I have a NextCloud server and use that to sync between it and my computer. I Calibre pointed at the library that is synced on the local computer. Never had an issue or any data loss. Been doing this for a couple of years now.