2.6.0 beta2へのアップデートを試みたところ、ウェブサイトに504エラーが表示

[thegurjyot (Gurjyot Singh)]

Ok I found the answers to this problem. Thanks to this answer the problem is finally solved.

Can't rebuilt app, says you have less than 5GB space on the disk

Discourse needs much more disk space than the size of the backup, in fact it’s the complete Discourse docker image that runs a database server, redis and much more plus all the uncompressed data. You can check the real occupied space on your system via df -h Although it might be already performed by recovering space during rebuild, you can try this apt-get autoclean apt-get autoremove cd /var/discourse ./launcher cleanup