Controlling thumbnail generation on a Synology NAS

Synology NASI’ve had a Synology NAS (an old DS107+, one of the earliest models) for several years now, and I love it for its simplicity of use and low energy/noise footprint as a home file/media server. I also like the fact that Synology does a pretty good job, for the most part, of keeping the software up to date and introducing nice new features.

However, when I upgraded my unit to version 3.1 of their Disk Station Manager (DSM) last week, I found that they had added a very undesirable “feature” which generates large thumbnail images for anything in your photo directory, apparently for use with the iPad app. Since I neither have an iPad nor have even enabled the PhotoStation component of the DSM software (which provides for a hosted web photo gallery–no thanks, I’m fine with Picasa web albums), I just wanted to turn this off. Furthermore, I found within a couple days of installing the update that the thumbnail generation process was constantly churning the disk and running the CPU at 100%, to the degree that normal file serving operations ran poorly. With the thumbnail process running, the unit could no longer even keep up with simple operations such as watching a video from the server over the normal Samba shares.

To my dismay, there is no option in the extensive DSM user interface to turn off this feature. I remember being slightly annoyed at this in previous versions, but it only made the system unusable once they added the XL thumbnails for the iPad app. (I have an nightly script that backs up my photo library to an offsite host via rsync every night, and I’d written it to ignore the @eaDir directories where the thumbnails are stored.) The synology forums seemed to be full of a lot of confused people trying to figure out how to turn off the thumbnail generation, but I was eventually able to identify the two key parts of the system that affect this.

If you want to simply disable XL thumbnail generation and leave everything else as-is, the file to edit is /usr/syno/etc.defaults/thumb.conf. You need to edit this file to remove the block starting with [thumb 1280]:

[thumb 1280]

Note that there’s also a /usr/syno/etc/thumb.conf, but on my system it didn’t have an XL thumbnail block so apparently the file in etc.defaults was overriding it. (BTW if you need help getting an ssh session into your box and editing files, there’s lots of help for that on the Synology site. I logged in as root and used vi.)

The thumb.conf file is read by a thumbnail generation daemon (service) that is started through /usr/syno/etc/rc.d/ So after editing the thumb.conf file you can either restart your system, or just restart this service:

/usr/syno/etc/rc.d/ stop
/usr/syno/etc/rc.d/ start

Once I did this, I no longer had “convert” processes at the top of my process list churning the hard drive and maxing out the CPU.

Alternatively, it sounds like you can also just prevent the thumbnail daemon from running at all on system startup. The rc scripts work a little differently from other *nix systems that I’ve used (although it’s been awhile); renaming the file didn’t appear to prevent it from starting when I tried that. The Synology wiki recommends adding a premature “exit” line right after the initial #!/bin/sh as a means of preventing a service from starting automatically (or ever, actually). I may go ahead and deactivate the process at some point but for now I was just satisfied that the XL thumbnails weren’t being generated.

In closing: Hey, Synology! Nice idea about the iPad gallery, but how about making it an option, once that’s not on by default, and with the warning that it will make older units practically unusable for their main purpose if activated?! I figured it out, but I’ve got some experience with *nix systems and the command line. I can see how a normal consumer user could be left completely helpless trying to address this problem and most likely end up blaming it on a (nonexistent) hardware fault.

30 Responses to “Controlling thumbnail generation on a Synology NAS”

  1. Danial says:

    Many thanks! it worked as you mentioned. Now, all I have to do is to find what tops ffmpeg to 100%.

  2. Matt says:

    Cool thanks, works a treat. Do you know where it will have dumped the thumbnails to get rid of them or did you just leave them?

  3. rdo says:


    The thumbnails are stored in subdirectories in each photo folder (I think they’re called @eaDir or something similar). You could potentially clean them out with a find command from the command line.

  4. Sam says:

    @RDO Thank you very much for sharing this.

    I had hard time using DS710+ for several days until I found what was the problem. I cannot imagine what other users are doing (especially those not with IT background and with lots of pics).

    Synology developers should have included thumb.conf configuration in Photo Station 4 setup, so people can choose what they size thumbs they would like THEIR system to generate.

  5. Chris says:

    I’ll put it in “Layman’s Terms” so others may remove the excessive space taken.

    You could format your storage and start from scratch.

    If that’s not acceptable, do what I did. But, this way is time consuming. There might be an easier (Automated way) way, but I don’t know. I’m not too savvy with Linux.

    Log into your Synology via root and type these commands:

    cd ..
    cd volume1 (not sure if this is the default name)
    cd photo
    From there you will see all of the different folders of pictures you have. Go into that folder.

    Then, you will want to navigate into each photo folder (Hint: If there are spaces, type: cd “There is a space.JPG” to change to that folder.

    Once your in that folder, go into this folder: cd @eaDir

    You will find 4 files with different sizes of the same picture. I just remove them all: rm *.*

    Once you are done, make sure to edit the thumb.conf file (Steps are above). Once you are done, just re-index your photos and let it build.

    I know *most* users know how to do this, but I decided to take it down a notch so others can fix this issue (If they need it).

    Hopefully Synology is taking care of this and will be fixed in their next release. From the quick updates, I’m sure this will be addressed in the near future.

  6. Chris says:

    UPDATE: Quick and EASY way to delete all of the large photos is to just disable the Photo Station 4. It erases all of the files under @eaDir. I’m not sure why I didn’t try that before..

  7. David says:

    Dear Munky, thanks for putting this info on the web. I installed a Ds211j over a week ago and copied over 19,500 photos. My CPU has run flat out 24/7 since and I still have 8000 photos to thumbnail. Sadly I do have an ipad and the idea of streaming photos to it was one of the reasons I went down the NAS route.
    Your other correspondents are right about performance however. Streaming music seems to work irratically for me at the moment.
    PS there is a facility within the photostation UI to postpobe the thumbnailling for few hours presumeably to allow you to do other things.
    Thanks again.

  8. Peter says:

    Thanks! Was searching for this for a few weeks. Was getting desperate :). I thought the guys from Synology were perfect. This was realy a big mistake. There is also no solution on the forum. I assume they read it as wel. Itsa shame.
    Thanks again!

  9. Anil says:

    Sure, we can delete the @eaDir forlder, but I am wondering if it break the photo station!!! I mean, does the photostation work without this forlde?

  10. vito says:

    Finally!!!! TNKs 😉
    Cheers from Italy!!!!

  11. thierry says:


    I tried your tips, inserting “exit” into the script.
    It seams that it stop the creation of thumbnail and @eaDir in the photo directorie.

    But the creation of the thumbnail and @eaDir continue into the Music and Video directorie.

    So the multimedia serveur files indexation create thumbnail also for music and video.

    May be an other script launch the synomkthumbd, synothumb, convert or dcraw proc

    I realy like that media server just index file without creating any directories and thumbnails…..

  12. TimO says:

    Yeah, I have telnet-ed and found the thumb.conf file but I cant edit it? As far I can tell I have permission to (i.e. -rw-r–r–) but when I open in vi and delete the lines and try and save it says it’s read-only?

  13. TimO says:

    Ok, thanks for the help (offline) Ryan. I have removed the unsharp lines (as I have an iPad so need the 1280 thumbnails I think) but I couldn’t stop / start the service. Say file not found but it listed it in DIR. Weird. So a hard reboot and let’s see …

  14. Checkeys says:

    The dcraw process is consuming my cpu power as well (DSM 4.0 Beta, DS212J and Photostation 5)

  15. Monkeyman says:

    I’m having the same problem as Timo (seems he got help offline)… how do I edit this thumb.conf file and save it ? When trying to edit the file & save it I get the the ‘read-only’ message.. (I logged as admin)

    I’m also a telnet noob .. (googled myself the commands into ‘vi’ …)

  16. Sven says:

    Hey Monkeyman,

    just log in with username “root” and you administrative password :-)

  17. Anonymous says:

    THANKS for the hints. I just renamed the two files thumb.conf and thumbs_high.conf to *.SAVE in both dirs (just to be on the safe side) and restarted the deamon. No conversion any more!

  18. Prof Yaffle says:

    I think the offending files are,, and

    You can use “exit” to crash out of them, or make them non-executable – or even unreadable with chmod 000 on each of them. Should stop them from running.

  19. […] Controlling thumbnail generation on a Synology NAS | […]

  20. mad max says:

    thanks Prof Yaffle

    i have used the edited the files you mentioned with “exit” using VI.

    synology should be shamed, they still have not given users a configurable option.

  21. Marius says:

    Be aware that this coredumps the process on Synology DSM 4.1 Beta.

    Be ready to remove this or else many people with get problems.

  22. FoZo says:


    when I delete

    [thumb 1280]

    I get this error in my message log:

    Sep 20 11:02:07 synomkthumbd: synomkthumbd.c:536 Failed to MKThumbExecv synothumb, file […file_path…]

    Do you have any solution for this problem?

  23. mildkiller says:

    thanks a lot! it rocks!

    only a tiny issue: once removed XL thumb, the photostation can’t show the thumbs of photos. I wonder which size of thumb the photostation requires? I’m OK if it displays S, M and L but now it doesn’t show anything, only a progress sign keeps turning around when I browse the photostation. Your solution is just one step to perfect but it’s still excellent! thanks again.

  24. Ben says:

    I had the same problem with making thumbnails after doing this as FoZo:

    synomkthumbd: synomkthumbd.c:563 Failed to MKThumbExecv synothumb

    I had to restore the etc.defaults/thumbs.conf back to original for it to even work (i.e. I added the 1280 block again)

  25. Ronald says:

    Does anybody have the content of I have overwritten it by mistake.

  26. Delphi says:

    In Control Panel>Media Indexing Service>Conversion Settings one can choose between normal and high thumbnails quality.

    If I select “normal quality”, will my synology still generate XL thumbnails?

  27. Jandirk says:

    I’m sorry but I’m quite a noob. I can not locate /usr/syno/etc/thumb.conf. I connected to my NAS with ssh but i cannot locate the file to edit. Is there a way to open the directory in my file explorer in windows

  28. david says:

    I had this problem too.

    Disable PhotoStation if you don’t want media Indexing.
    Alterantively you can switch off media indexing (might need a reboot)

    But I do want the thumbnails!

    Checking several links on google, I discovered that you should use your computer to upload it using Synology’s Photo Station PC/Mac application. That way it will use your CPU to create thumbnails not the puny one in the NAS.

    Download the latest Photo Station at Synology website.

    I’m trying it now… if you don’t hear back from me, it works. =)

  29. Dedi says:

    You can disable the indexing without have to edit the thumb file. Go to /usr/syno/bin, run disable PhotoStation or MediaServer. alternative you can directly go to /usr/syno/etc/synoindex/packages/PhotoStation/INFO, update the file using vi from enabled=yes to no.

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