It is frequently said that for PostgreSQL the number 1 thing to pay attention to when increasing performance is the amount of IOPS a storage system is capable of. Now I wonder if there is any situation in which sequential IO performance comes into play. E.g. perhaps during a tablescan on a non-fragmented table, or during a backup or restore?
The reason I'm asking is that we're building a storage array and for some reason are unable to increase the number of random IOPS beyond a certain threshold when we add more controllers or more (SSD) disks to the system. However, the sequential performance keeps increasing when we do that.
Would this extra sequential performance be of any benefit to PG or would it just be wasted?