is cloudflare Cache Reserve necessary

I just think about cloudflare Cache Reserve if it is really necessary,

– Well, yes if you have a low-traffic site. But not really if you have a mid-high to high traffic site.

Cause if you have a mid-high to high traffic site with Smart Tiered Cache enabled, due to the high traffic Cloudflare will auto promote your cached contents to disk cache from transient cache. So, you will have good HIT ratio.

But if your site doesn’t have good traffic across all pages, Cloudflare will delete the cached contents from the Transient Cache after not seeing good traffic. So, Cache Reserve will exponentially increase your HIT ratio.

I think Cache Reserve just solve the problem of cache remain in cf tiere no more than 24 hours(I guess no more than 24 hours if not hit 2nd time)

– Really? But according to Cloudflare Docs the retention period is 30 days. Can you double check this with Cloudflare?

but as per tiered cached and cron job, I could hit my site map every day (such as every 23 hours once according to the (Super Page Cache for Cloudflare), that is save the cost of Cache Reserve, what do you think guys, am I right or I make something misunderstand?

– Not that simple, Cloudflare AI system can easily recognize your Cron jobs and not cache content. Also cache reserve means it will remain cached globally while in case of manual hit, it is only for the location you are hitting from and maybe the upper tier to that.

Does cloudflare Cache Reserve have many nodes or just store in one place (I guess it will not auto spread to many different nodes) to serve different T1, T2 nodes? (if just one, it may be not faster than my original server)

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– From My understanding, behind the scene it uses R2 service, so it will be basically everywhere. I guess the logic is that if lower tier doesn’t have it in cache, then it will as for cache to the upper tier, then if upper tier doesn’t have it in cache, it will check cache reserve and if cache is not there then fetch from origin.

As you said – mid-high traffic, how many traffic should consider mid-high?
If mid-high traffic – Smart Tiered Cache may enough
If low traffic, may need Cache Reserve
Am I right?

– I would say if you have 2,00,000 to 3,00,000 sessions/month then maybe you will be under the mid-traffic site. But again, that’s my number, I don’t have a formula for this.

because I ask this quesion just consider about the cost,

– You should definitely check: https://developers.cloudflare.com/cache/about/cache-reserve/#cache-reserve-billing-examples to understand the billing better.