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Comment by tptacek | Hacker News Reader

I'd have grave concerns about the security/integrity of data I stored in such a thing. People tend to store low-value data in memcache without realizing that corrupting it allows attackers to hijack user sessions.

What is the value of sharing a memcached instance? If all you're selling is memory, why not just run multiple memcacheds?

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Well, the thing is that today if you want a memcache on Linode, you need to rent another node. A linode 512MB is 20$/month.

But what If i only need 100MB of memcached, and I don't want to pay 20$/month for that ?

Sure, one could sell memcached memory, with many instances per linode node. But my question is more about getting super-lower memcached for not critical data (if people put sessions in it, they misuse the service, they take their risks..). By sharing the bucket with people, can you afford to pay 5$/month for a part of a 400MB bucket ?

Can you not run multiple memcached instances on the same node? Wouldn't this lower the cost just as much?

you can, but then it's like partitionned. I'm not sure people would pay for 50 or 100MB memcached near their VPS. That's another question.

Memcache is designed to be run on a trusted network and only accessed by trusted clients. Therefore sharing a memcache daemon in its current state is not recommended at all.

See http://www.slideshare.net/sensepost/cache-on-delivery on what can be done with a publicly accessible memcache daemon.

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