Migrating a large site from SQL Server to MongoDB - Lessons Learned

18 pointsrfurlan14y ago12 comments

SQL and NoSQL are different tools for different jobs. A couple of months ago we migrated a large site from SQL Server to MongoDB, it was a bumpy road and I decided to write this article to share what we learned: http://www.wireclub.com/development/TqnkQwQ8CxUYTVT90/read

18 pointsrfurlan14y ago12 comments

12 comments

9 comments · 4 top-level

amrith14y ago· 2 in thread

I'm shocked and mortified ... Check out http://bit.ly/v1cznd

Why would you conclude that MongoDB was "fast" and SQL Server was slow? Did you run SQL server on the same SSD's and multiple HDD's?

to willvarfar's comments, what was the real fsync cost and didn't you get ACID with SQL Server? Now, if ACID is not really required, and you really really need flexible schemas, then by all means ... I understand that you want distributed-queryable-notepad, not a relational database!

rfurlanOP14y ago

Also, I never said SQL Server is slow - it isn't, anyone that would say otherwise must have an agenda, which is not my case. SQL Server is an incredible database and it has served us well.

rfurlanOP14y ago

MongoDB has the potential to be faster than traditional relational databases simply because it does less, way less. The trade off makes sense for some applications, but not for all, it really depends on your requirements.

willvarfar14y ago· 2 in thread

So do you have fsync enabled?

rfurlanOP14y ago

fsync is enabled for the vast majority of calls and it is our default setting. Disabling fsync should be treated as case-by-case optimization IMO

latch14y ago

I assume when people talk about fsync, they actually mean journaling?

I'm not sure if there's ever a good reason to use {fsync: true} vs {j: true}

1 more reply

byoung214y ago· 1 in thread

Clickable: http://www.wireclub.com/development/TqnkQwQ8CxUYTVT90/read

rfurlanOP14y ago

Thanks byoung2!

rfurlanOP14y ago

I also hosted a Q&A about our experience here on HN: http://news.ycombinator.com/item?id=3141331

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