On Mar 30, 2013 7:13 PM, "Satoshi Nagayasu" <sn...@uptime.jp> wrote: > But I heard that larger block size, like 256kB, would take > advantage of the SSD performance because of the block management > within SSD.
This is only true for very bad SSDs. Any SSD that you would want to trust with your data do block remapping internally, eliminating the issue. (See for example Intel DC3700 sustaining 34'000 random 4k writes/s) Larger block sizes would just lift the random access workload write amplification into Postgresql where the drive can't fix it. For sequential or mostly sequential workloads the OS can take care of it by merging writes. Additionally, contention for page level locks will increase with page size, cache efficiency goes down. I would expect cases where larger block size is a significant benefit to be very rare. Regards, Ants Aasma
