Hi, I recently purchased a SATA Samsung 860 EVO SSD and put it in an old HP microserver (which has an AMD N36L). By default, when the disk load becomes a little heavy e.g. by running a job like fio --name=test --readonly --rw=randread --filename /dev/sdb --bs=32k \ --ioengine=libaio --iodepth=32 --direct=1 --runtime=10m --time_based=1 the kernel starts repeatedly producing error messages like: [ 1177.729912] ata2.00: exception Emask 0x10 SAct 0x3c000 SErr 0x0 action 0x6 frozen [ 1177.729931] ata2.00: irq_stat 0x08000000, interface fatal error [ 1177.729943] ata2.00: failed command: WRITE FPDMA QUEUED [ 1177.729962] ata2.00: cmd 61/80:70:80:50:e6/06:00:00:00:00/40 tag 14 ncq dma 851968 out [ 1177.729962] res 40/00:80:00:5a:e6/00:00:00:00:00/40 Emask 0x10 (ATA bus error) [ 1177.729978] ata2.00: status: { DRDY } [ 1177.729986] ata2.00: failed command: WRITE FPDMA QUEUED [ 1177.730002] ata2.00: cmd 61/00:78:00:57:e6/03:00:00:00:00/40 tag 15 ncq dma 393216 out [ 1177.730002] res 40/00:80:00:5a:e6/00:00:00:00:00/40 Emask 0x10 (ATA bus error) [ 1177.730017] ata2.00: status: { DRDY } [ 1177.730024] ata2.00: failed command: WRITE FPDMA QUEUED [ 1177.730039] ata2.00: cmd 61/00:80:00:5a:e6/05:00:00:00:00/40 tag 16 ncq dma 655360 out [ 1177.730039] res 40/00:80:00:5a:e6/00:00:00:00:00/40 Emask 0x10 (ATA bus error) [ 1177.730053] ata2.00: status: { DRDY } [ 1177.730060] ata2.00: failed command: WRITE FPDMA QUEUED [ 1177.730078] ata2.00: cmd 61/00:88:00:5f:e6/01:00:00:00:00/40 tag 17 ncq dma 131072 out [ 1177.730078] res 40/00:80:00:5a:e6/00:00:00:00:00/40 Emask 0x10 (ATA bus error) [ 1177.730096] ata2.00: status: { DRDY } [ 1177.730108] ata2: hard resetting link [ 1178.205831] ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300) [ 1178.206165] ata2.00: supports DRM functions and may not be fully accessible [ 1178.209743] ata2.00: supports DRM functions and may not be fully accessible [ 1178.212786] ata2.00: configured for UDMA/133 [ 1178.212826] ata2: EH complete [ 1178.212988] ata2.00: Enabling discard_zeroes_data I tried moving the SSD to another caddy and bay but the issue persists. None of the regular hard disks (a Western Digital and a Seagate) nor the other SSD (a Crucial MX500) already in the system trigger the issue the Samsung 860 EVO does. Adding libata.force=2.00:noncq seems to make the issue go away but seemingly at some speed cost (at least compared to what the MX500 achieves). The OS in use is Ubuntu 18.04 with a 4.15.0-43-generic kernel but even a 4.18.0-13-generic had the same issue. Is there anything software-wise that might need investigating that would allow NCQ to work and a better speed to be reached? -- Sitsofe | http://sucs.org/~sits/