[OmniOS-discuss] smartctl and SCT ERC on omnios

[Andrew Kinney]

Hello,

I have a Samsung 845DC Pro SSD that I need to respond more timely during 
problems with flash cells. We had an incident where it took 2 minutes to 
fail a cell erase and bring in a spare cell, which is too long for a 
redundant ZFS log device on a pool with a dataset with property 
sync=always serving iSCSI volumes.

smartctl shows it supports SCT ERC:

# smartctl -x -d sat,12 /dev/rdsk/c4t0d0s0

smartctl 6.5 2016-05-07 r4318 [i386-pc-solaris2.11] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model:     Samsung SSD 845DC PRO 400GB
<snip>
ATA Version is:   ACS-2, ATA8-ACS T13/1699-D revision 4c
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
<snip>
SCT capabilities:              (0x003d) SCT Status supported.
                                         SCT Error Recovery Control 
supported.
                                         SCT Feature Control supported.
                                         SCT Data Table supported.
<snip>


I should be able to read its current SCT ERC settings, but get an error:

# smartctl -l scterc -d sat,12 /dev/rdsk/c4t0d0s0
smartctl 6.5 2016-05-07 r4318 [i386-pc-solaris2.11] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

SMART WRITE LOG returns COUNT and LBA_LOW register unchanged
SCT (Get) Error Recovery Control command failed


I would go read/write the scterc values on a different OS as a 
workaround, but I've read that Samsung devices do not persist CCTL 
values across reboots. At present, I don't know what it's set to or if 
it's being honored.

It appears that this is a limitation of smartmontools on Solaris and its 
derivatives.

Any ideas how I can read and set the scterc values on Omnios?

--
Andrew