[snissn]

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

[dhd415]

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.

[slagfart]

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

[estefan]

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...

[dhd415]

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.

[estefan]

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).