3 ms·

Maybe I'm being the kind of developer that the blogger was talking about, but would it be such a bad idea for a Mailinator like site to use Redis to store the e

by Simucal 15y ago

Maybe I'm being the kind of developer that the blogger was talking about, but would it be such a bad idea for a Mailinator like site to use Redis to store the email messages but hosted on the same box as the web server? At least that way, if you started to hit memory limits it would be relatively simple to scale out to more machines by moving Redis to its own box. It would be a configuration change rather than having to re-architect your custom LRU cache. Another benefit would be that you could get disk persistence for free while still staying fast. If Mailinator needs to reboot all the emails are lost. That wouldn't necessarily have to happen if he was using Redis.

tomjen3 15y ago
Actually the best way would be to write a facade which would allow him to change between implementations -- so he could switch between his custom LRU, Redis and any mixture he he wrote later (say a custom version of memcache or memcacheDB).
deleted 15y ago
[deleted]
cmarshall 15y ago
Running Redis on the same server still adds overhead to the system, to store an object in a map that's on the Java heap doesn't require any inter-process communication or serialization. Plus it's another point of failure, what if the Redis process stops but the Java process is still running? If Redis is remote, what happens if the network goes down? Keeping everything within the JVM avoids having to think about those failure scenarios. I don't know how Mailinator is coded, but I'd guess he hasn't written anything too custom for storing key/value pairs in memory, there are plenty of Java caching implementations, the key thing he has done is work out a way of reducing the duplication, which Redis won't provide out of the box. Mailinator is a great example of having the minimal set of features required and no more. There's no logins, no setup steps and no guarantees. This allows Mailinator to run on such minimal hardware, adding disk persistence would add complication without making the product better, by definition the kind of emails you send to Mailinator aren't important, so if they're lost during the occasional restart it doesn't detract from the service.

by Simucal 15y ago

tomjen3 15y ago

Actually the best way would be to write a facade which would allow him to change between implementations -- so he could switch between his custom LRU, Redis and any mixture he he wrote later (say a custom version of memcache or memcacheDB).

deleted 15y ago

[deleted]

cmarshall 15y ago

Running Redis on the same server still adds overhead to the system, to store an object in a map that's on the Java heap doesn't require any inter-process communication or serialization. Plus it's another point of failure, what if the Redis process stops but the Java process is still running? If Redis is remote, what happens if the network goes down? Keeping everything within the JVM avoids having to think about those failure scenarios. I don't know how Mailinator is coded, but I'd guess he hasn't written anything too custom for storing key/value pairs in memory, there are plenty of Java caching implementations, the key thing he has done is work out a way of reducing the duplication, which Redis won't provide out of the box. Mailinator is a great example of having the minimal set of features required and no more. There's no logins, no setup steps and no guarantees. This allows Mailinator to run on such minimal hardware, adding disk persistence would add complication without making the product better, by definition the kind of emails you send to Mailinator aren't important, so if they're lost during the occasional restart it doesn't detract from the service.