On our RHEL 7.2 server we saw a strange kernel messages with lines as:
Disabling DIF Type 2 protection
***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
Above messages are relevant for all disks in the server ( DELL HW MACHINE )
Example of dmesg
[ 4.637635] sd 0:2:0:0: [sdm] ***10DIGITS*** 512-byte logical blocks: (599 GB/558 GiB)
[ 4.637668] sd 0:2:0:0: [sdm] Write Protect is off
[ 4.637670] sd 0:2:0:0: [sdm] Mode Sense: 1f 00 00 08
[ 4.637690] sd 0:2:0:0: [sdm] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[ 4.637705] sd 0:0:5:0: [sdf] Disabling DIF Type 2 protection
[ 4.637713] sd 0:0:5:0: [sdf] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.638024] sdm: sdm1 sdm2
[ 4.638914] sd 0:2:0:0: [sdm] Attached SCSI disk
[ 4.639623] sd 0:0:0:0: [sda] Disabling DIF Type 2 protection
[ 4.639630] sd 0:0:0:0: [sda] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.640577] sd 0:0:5:0: [sdf] Write Protect is off
[ 4.640580] sd 0:0:5:0: [sdf] Mode Sense: d7 00 10 08
[ 4.641773] sd 0:0:5:0: [sdf] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.642697] sd 0:0:0:0: [sda] Write Protect is off
[ 4.642699] sd 0:0:0:0: [sda] Mode Sense: d3 00 10 08
[ 4.643679] sd 0:0:7:0: [sdh] Disabling DIF Type 2 protection
[ 4.643681] sd 0:0:7:0: [sdh] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.643969] sd 0:0:2:0: [sdc] Disabling DIF Type 2 protection
[ 4.643975] sd 0:0:2:0: [sdc] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.644348] sd 0:0:8:0: [sdi] Disabling DIF Type 2 protection
[ 4.644354] sd 0:0:8:0: [sdi] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.645693] sd 0:0:1:0: [sdb] Disabling DIF Type 2 protection
[ 4.645696] sd 0:0:1:0: [sdb] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.645845] sd 0:0:4:0: [sde] Disabling DIF Type 2 protection
[ 4.645848] sd 0:0:4:0: [sde] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.646360] sd 0:0:7:0: [sdh] Write Protect is off
[ 4.646362] sd 0:0:7:0: [sdh] Mode Sense: d7 00 10 08
[ 4.646780] sd 0:0:2:0: [sdc] Write Protect is off
[ 4.646781] sd 0:0:2:0: [sdc] Mode Sense: d7 00 10 08
[ 4.647030] sd 0:0:8:0: [sdi] Write Protect is off
[ 4.647035] sd 0:0:8:0: [sdi] Mode Sense: d7 00 10 08
[ 4.647087] sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.647365] sd 0:0:3:0: [sdd] Disabling DIF Type 2 protection
[ 4.647368] sd 0:0:3:0: [sdd] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.647622] sd 0:0:7:0: [sdh] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.647977] sd 0:0:2:0: [sdc] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.648294] sd 0:0:8:0: [sdi] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.648389] sd 0:0:1:0: [sdb] Write Protect is off
[ 4.648390] sd 0:0:1:0: [sdb] Mode Sense: d7 00 10 08
[ 4.648514] sd 0:0:4:0: [sde] Write Protect is off
[ 4.648516] sd 0:0:4:0: [sde] Mode Sense: d7 00 10 08
[ 4.649369] sd 0:0:9:0: [sdj] Disabling DIF Type 2 protection
[ 4.649372] sd 0:0:9:0: [sdj] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.649578] sd 0:0:1:0: [sdb] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.649708] sd 0:0:4:0: [sde] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.650046] sd 0:0:3:0: [sdd] Write Protect is off
[ 4.650052] sd 0:0:3:0: [sdd] Mode Sense: d7 00 10 08
[ 4.650371] sd 0:0:16:0: [sdl] Disabling DIF Type 2 protection
[ 4.650376] sd 0:0:16:0: [sdl] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.651296] sd 0:0:3:0: [sdd] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.652099] sd 0:0:9:0: [sdj] Write Protect is off
[ 4.652101] sd 0:0:9:0: [sdj] Mode Sense: d7 00 10 08
[ 4.653189] sd 0:0:6:0: [sdg] Disabling DIF Type 2 protection
[ 4.653192] sd 0:0:6:0: [sdg] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.653201] sd 0:0:16:0: [sdl] Write Protect is off
[ 4.653203] sd 0:0:16:0: [sdl] Mode Sense: d7 00 10 08
[ 4.653285] sd 0:0:9:0: [sdj] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.653495] sd 0:0:14:0: [sdk] Disabling DIF Type 2 protection
[ 4.653498] sd 0:0:14:0: [sdk] ***10DIGITS*** 512-byte logical blocks: (2.00 TB/1.81 TiB)
[ 4.654397] sd 0:0:16:0: [sdl] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.654474] sd 0:0:5:0: [sdf] Attached SCSI disk
[ 4.655990] sd 0:0:6:0: [sdg] Write Protect is off
[ 4.655993] sd 0:0:6:0: [sdg] Mode Sense: d7 00 10 08
[ 4.656204] sd 0:0:14:0: [sdk] Write Protect is off
[ 4.656210] sd 0:0:14:0: [sdk] Mode Sense: d7 00 10 08
[ 4.657189] sd 0:0:6:0: [sdg] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.657431] sd 0:0:14:0: [sdk] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 4.660959] sd 0:0:8:0: [sdi] Attached SCSI disk
[ 4.662148] sd 0:0:1:0: [sdb] Attached SCSI disk
[ 4.662206] sd 0:0:7:0: [sdh] Attached SCSI disk
[ 4.662350] sd 0:0:4:0: [sde] Attached SCSI disk
[ 4.662387] sd 0:0:2:0: [sdc] Attached SCSI disk
[ 4.665915] sd 0:0:9:0: [sdj] Attached SCSI disk
[ 4.665985] sd 0:0:3:0: [sdd] Attached SCSI disk
[ 4.666962] sd 0:0:16:0: [sdl] Attached SCSI disk
[ 4.671749] sd 0:0:14:0: [sdk] Attached SCSI disk
[ 4.672000] sd 0:0:6:0: [sdg] Attached SCSI disk
[ 4.681089] sd 0:0:0:0: [sda] Attached SCSI disk
Do we need to be worry about those messages ?
Notes:
- Server is include physical disks as sdb / sdc /sdd /sde etc ..
- The reason for our investigation is CPU high load avrg
