Estimate server specs after migrating from vBulletin5 to Discourse


I’m migrating a forum to Discourse.
Unfortunately, the current vBulletin forum is broken and I don’t have access to the forum monthly stats.

This is what I know and I could estimate (based on several homepage snapshots from :sweat_smile:):

  • 180000 users (including a lot of spam accounts what weren’t blocked…)
  • 1.6M posts (including topics) note that the forum is 20 years old and the activity was peaking in the 2000s, not so much nowadays
  • ±10 users and 800 visitors at any given time
  • ± 20 posts per day
  • The full vbulletin database including avatars and attachments is 13 GB.

Daily stats expecting to rise (hopefully!) when the forum opens again.

With this info, can you estimate which specs I’d need? I’ll rent a server on Hetzner, this is their VPS specs lists:

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I’d probably start with CPX51 because the numbers look like a lot of activity but you could probably get away with CPX41 if the traffic volume isn’t expected to grow much.

Ideally, I’d want to leverage S3 and CDN to offset some load.


CDN is essential to reduce load. S3 isn’t as essential unless you feel you are going to have a community of compulsive giant-image-uploaders :wink:


Hi, thanks for your replies. I know nothing about CDN, so I’m going to learn what it is exactly, how it works and how it would impact Discourse’s performances.

With my experience you can start without any issue with a CPX11 my only worry is the Disk Space as you will fill it pretty quickly. Like OOO you’ll have a 65-70% disk usage, so just to avoid soon off line time for upgrade I’d go with CPX21 but not because you need the Horse Power in the server.

Other option is to host all the uploads in a S3 or S3 like offering, the thing is that I’m almost sure that Hetzner doesn’t offer this product yet. Using S3 would allow you to offload all the attachments to another hosting which is a lot cheaper.

The CDN is a Content Delivery Network this service will cache your most used static assets as JS, images, etc. and distributed in multiple Point of Presence (PoPs) which lower the load on your server and increase the load speed if your community is spread in multiple regions.

If you want you can send me a PM and can give you some more advice.


I Prefer S3 (at least for Backup storage) Just for the added peace of mind that one copy of backup is offsite.


I intend to use 3S to backup my website in addition to local backups, but not for uploads as I don’t think it would be really useful, but I need to think about that more and search for more information.

Hetzner servers are scalables and I can upscale/downscale in seconds (can’t decrease disk size though), but I prefer to start on right specs estimation than doing things 100% empirically. :slight_smile:

Also my uploads take 7 GB of disk size.

Thank you very much for this quick explanation. My community is international, so it will probably help.

Just so you have a little more information as comparison and the reason of why I estimate that CPX11 would be enough if it has just a little bit more of Disk Space.

My community receives (daily):

  • Registered users visits: 500-750
  • Anonymous users visits: 2300-3000
  • Topics: 2
  • Posts: 10-30

I’m running a 1vCPU and 2GB RAM setup and haven’t found any performance issue.

The issue is (as always is) that each person visiting at the same time will need some server resources (CPU/RAM) if you use a CDN this needs reduce greatly as most of the load of finding the files and shipping them to the user is offloaded of your server.

Now, the specs of your server will be tied to your disk space and to how many users decide to visit the site at the same time.