How to cache ghost posts?

Developer help
1

I ran a benchmark using `ab -r -n 1000 -c 10 https://
just by running this several mysql processes came up and whole website was slowed down.

Config: Digital ocean
2GB RAM & 1 CPU

I think there needs to be a caching layer(from my side) on top of ghost which can do full page cache and avoid database hits.
Can someone provide me some info on this?

2

Varnish is great for caching content. You can configure varnish to never cache API / Admin requests, but listen to those requests since they have cache invalidation headers

3

Do you have any hardware recommendations for using Varnish? Do you cache in memory or on disk?

4

As far as I’m aware, Varnish supports both in-memory and disk storage for caches. You don’t need powerful hardware to run Varnish; a $5 DO droplet with Ghost and Varnish should be adequate.

5

Yes it does, I was curious what your implementation choices were.

a $5 DO droplet with Ghost and Varnish should be adequate.

That’s good to know, as that’s the droplet I’m using right now and I wanted to cache in memory but was concerned that this tier of droplet wouldn’t have enough memory.

6

You can always use swap if needed. I configured Varnish on my site (which isn’t very active) a couple years ago, and I manually purge caches when I update posts since that doesn’t happen often.

As an aside, all of this discussion is relative to size; if you have thousands of posts, a $5 droplet probably won’t suffice.

7

Yeah I guess I’ll just have to give it a try and watch memory consumption. I’ll have to look into how to use swap on a DO droplet.

8

I used caddy server on top of Ghost. It’s cache mechanism did increased my website req/s. I did full page cache but I can’t flush cache or avodi homepage cache.

Can I do that in varnish without getting into terminal?
And do you prefer ghost + nginx + varnish or just ghost + varnish?

9

Not that I’m aware. Varnish uses a compiled configuration mechanism and I think you need terminal access to make changes. Questions like these are better suited for your host.

My configuration is ghost->varnish->nginx but as far as I’m aware, varnish is capable of serving as a web server

11

@vikaspotluri123 do you have an example of your Varnish config files? I’m trying to setup Varnish on a DO droplet running Nginx.

12

It’s been a long time since I configured this (including before Memberships was a thing in Ghost), and I am not very experienced with Varnish, but here’s a majority of the config:

#
# This is an example VCL file for Varnish.
#
# It does not do anything by default, delegating control to the
# builtin VCL. The builtin VCL is called when there is no explicit
# return statement.
#
# See the VCL chapters in the Users Guide at https://www.varnish-cache.org/docs/
# and http://varnish-cache.org/trac/wiki/VCLExamples for more examples.

# Marker to tell the VCL compiler that this VCL has been adapted to the
# new 4.0 format.
vcl 4.0;

# Default backend definition. Set this to point to your content server.
backend default {
    .host = "127.0.0.1";
    .port = "80";
}

backend ghost {
    .host = "127.0.0.1";
    .port = "2372";
}

sub vcl_recv {
    if (req.method == "PURGE") {
        return (purge);
    }

    # Happens before we check if we have this in cache already.
    #
    # Typically you clean up the request here, removing cookies you don't need,
    # rewriting the request, etc.

    if (req.http.host == "ghost.yoursite.org") {
        set req.backend_hint = ghost;
    }

    if ( req.url !~ "/ghost/" && req.url !~ "/p/" ) {
        unset req.http.cookie;
    }
}

sub vcl_backend_response {
    # Happens after we have read the response headers from the backend.
    #
    # Here you clean the response headers, removing silly Set-Cookie headers
    # and other mistakes your backend does.

    set beresp.ttl = 5m;
}

sub vcl_deliver {
    # Happens when we have all the pieces we need, and are about to send the
    # response to the client.
    #
    # You can do accounting or modifying the final object here.

   if ( req.url ~ "/ghost/" || req.url ~ "/signout" || req.url ~ "/p/" ) {
        set resp.http.Cache-Control = "no-cache, private, no-store, must-revalidate, max-stale=0, post-check=0, pre-check=0";
        set resp.http.expires = "0";
    }

    if (obj.hits > 0) {
        set resp.http.X-Cache = "HIT";
    } else {
        set resp.http.X-Cache = "MISS";
    }

    set resp.http.X-Proxy-Cache = "1";
}
13

Just as an aside; Ghost minimum requirements state it needs at least a 2GB RAM, so $5 DO Droplets won’t cover it. It needs to be the $10 one’s at bare minimum.

14

Where do you see that? It says 1gb here:

15

That’s odd, I swore I read somewhere it was 2GB. My apologies if that’s not the case.