Re: HighPoint RocketRaid 620 vs. RocketRaid 640 -- supported?

From: Justin Piszcz
Date: Mon Oct 03 2011 - 16:17:00 EST

On Mon, 3 Oct 2011, Pasi Kärkkäinen wrote:

On Wed, Sep 21, 2011 at 07:28:26AM -0400, Justin Piszcz wrote:

Incase anyone is wondering the same thing, I contacted Highpoint and they
said (confirmed) the 620 support (which I am using now) is built-in to
the kernel and the 640 is not, so unless you like compiling kernel
modules/out of tree drivers for a _boot_ volume and want a regular SATA
6.0gbps controller that supports TRIM, I'd go for the 620 even though it
maxes out around 390-420MiB/s read where a real SAS controller supports
490-500MiB/s for an Intel 510 SSD, but remember, SAS controllers (at
least the one I tested with does not support TRIM and there is no Intel
SSD optimizer for Linux.

Hmm.. does SAS "SCSI UNMAP" automatically get translated to
ATA TRIM if you hook up SATA disk to SAS HBA ?
When attached to a SAS HBA, it simply says:

Jul 14 16:12:03 p34 kernel: [ 22.258855] EXT4-fs warning (device sda2): release_blocks_on_commit:2679: discard not supported, disabling

Is the ATA<->SCSI translation being done by the HBA firmware,
or is it handled in the driver?
I'm not sure, it would appear the driver handles it, when its on the Sata 6gbps
card (not SAS), it works fine:
Sep 20 13:53:34 p34 kernel: [ 6.786898] EXT4-fs (sdb2): re-mounted. Opts: discard

-- Pasi (who is too lazy to grep in the driver right now ;)