Hi,
Something interesting to note:
When I have an Intel 510 SSD plugged into an mpt2sas board, discard (TRIM) is not supported:
[ 16.483409] EXT4-fs (sda2): re-mounted. Opts: discard
[ 17.814743] EXT4-fs warning (device sda2): release_blocks_on_commit:2679: discard not supported, disabling
With a regular SATA port or an (PCI-e 2.0 x1 card), it works but with the overhead, PCI-e x1 seems to peak around 400-430MiB/s for reads, whereas with an X8 SAS controller I see 480-495MiB/s as the benchmarks show on various websites, ah well, its one thing or the other.
Justin.