I'm setting up a dedicated linux postgres box with 2x300GB 15k SAS drive in a RAID 1, though if future load dictates we would like to be able to upgrade to RAID 10. The hosting provider offers the following options for a RAID controller (all are the same price):
ADAPTEC 3405 RAID Controller
ADAPTEC 4800 RAID Controller
LSI MegaRaid 8308 RAID Controller
ADAPTEC 5405 RAID Controller
ADAPTEC 5405Z RAID Controller
ADAPTEC 5805 RAID Controller
ADAPTEC 5805Z RAID Controller
However, they can't guarantee that any particular RAID controller would be in stock when they are building the machine, so basically I would like to know if any of these cards are sufficiently better or worse than the others that I should either a) wait for a particular card or b) avoid a card.
Also, I am planning on replicating this box to a standby machine with streaming replication. Given this, is there any reason not to use the write cache on the RAID controller assuming it has battery backup? My though being even in a worst case scenario if the BBU fails and the master DB gets corrupted, the standby (not using any write cache) would still be ok sans a few seconds of data (assuming the replication was keeping up, which would be monitored).
-Dan