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Comment by snissn | Hacker News Reader

Does anyone else have abysmal IO performance on postgres RDS? I have a 200 gb provisioned ssd with 2000 iops and get abysmal bulk read performance - the panel will report 30 mb/s and query speed is really slow with disk being the bottleneck

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I'm using RDS MySQL and have never been able to utilize more than ~25% of the provisioned IOPS or more than 100MB/s transfer rate. Also, as best as I can tell, EBS latency is pretty high so making lots of small, serial database calls is a lot slower than it would be on local disks.

Any indexes on the table? Are you using COPY, INSERT INTO or /COPY via PSQL?

IIRC there are various tricks you used to have to perform to get it to strip across different disks in the backend. Something along the lines of allocating 20% of your storage and then increasing it 5 times until you had what you wanted. If you provisioned a server immediately to full capacity you'd end up with your data too close together which degraded performance.

That's something I heard that used to be true but not sure whether it's still required with upgrades to S3 over the years...

Interesting, I've never heard of striping tricks like that. Do you have any links on that? And I suppose that could be applicable to EBS since it rather than S3 is the backing store for RDS.

Sorry I don't have links. But yes, I think it was primarily to improve the performance of EBS, not S3 (been a while since I had to work on that sort of thing).

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