raid0 tends to linear scaling so 3 of them should give something close to 300% increased write speed. So i would say 1. but make sure you test your configuration as soon as you can with bonnie++ or something similar
I have a server with 32GB ram, one intel E3-1245 and four 15k SAS disks with a BB LSI MegaRaid controller. I wan't the optimal performance for my server, which will be pretty write heavy at times, and less optimized for redundancy, as my data is not very crucial and I will be running a streaming replication along side.
Now what would you prefer:
1) 3 disks in RAID 0 containing PGDATA + 1 containing SYSTEM and WAL 2) All four in RAID 10 containing both PGDATA, SYSTEM AND WAL 3) 2 disks in RAID 1 containing PGDATA + 2 disks in RAID 1 containing SYSTEM and WAL 4) Something different?
A 5. option could also be to simply have all 4 disk in a RAID 0 containing all PGDATA, SYSTEM and WAL
