On Mon, Nov 11, 2013 at 7:39 PM, Brad Campbell
[off-list ref] wrote:

On 11/07/2013 06:54 PM, Justin Piszcz wrote:

quoted

On Mon, Nov 4, 2013 at 5:25 AM, Justin Piszcz [off-list ref]
wrote:

quoted

Hi,

I run two SSDs in a RAID-1 configuration and I have a swap partition on a
third SSD.  Over time, the mismatch_cnt between the two devices grows
higher
and higher.

Are both SSD's identical? Do you have discard enabled on the filesystem?

Yes (2 x Intel SSDSC2CW240A3) & yes )/dev/root on / type ext4
(rw,relatime,discard,data=ordered))

The reason I ask is I have a RAID10 comprised of 3 Intel and 3 Samsung
SSD's. The Intel return 0 after TRIM while the Samsung don't, so I _always_
have a massive mismatch_cnt after I run fstrim. I never use a repair
operation as it's just going to re-write the already trimmed sectors.

Very interesting and good to know!

Justin.