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Comment by caw | Hacker News Reader

My company is currently using Mongo, and while it works, I wouldn't recommend it. We're looking at Cassandra and Elasticsearch, which seems to be a lot more promising.

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Beware of using Elasticsearch as a primary DB. Kyle Kingsbury has shown that it loses an awful lot of data during a partition, despite their claims. Example: http://aphyr.com/posts/317-call-me-maybe-elasticsearch

I think with $70m+ in funding, ES has the resources to fix their split brain issues.

I've only had about a year and a half of working in that space, but can confirm that Cassandra's quite good for truly huge time-series data. If you want to record an event every time someone makes a purchase at a Wal-Mart, turn to Cassandra or a similar system.

It is also much more highly regarded as a primary data store than Elasticsearch.

The number of horror stories I've seen about mongo is up to around 10 this month alone.

I'm now glad I never made the jump... in the meantime, pgsql is still on my list

I wouldn't say it's a horror story, it's just not really for time series "big data". The backend guys have had to muck about with the data a lot to get good performance out of it. There's some optimizations we missed on the sysadmin side too, like sharding the cluster after it got to ~250GB, and now it's many times that. Our Mongo clusters have been running production for well over a year.

We had a 50gb instance initially and it was no problem, then our app started to get a lot more traffic in a short period of time. We had to start sharding on a reasonably large scale. Mongo is a lot harder to maintain when it's big and unpredictable. I know this sounds like a plug, alas it's the truth, we found Object Rocket and now we don't worry about Mongo.

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