Hi! I've also reproduced this issue on this kernel Linux desktop 4.10.0-28-generic #32~16.04.2-Ubuntu SMP Thu Jul 20 10:19:48 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux ==================== Each one second, my program reads /sys/block/$DEVICE/stat. It substracts previously saved values, then saves current values, so I know the hdd activity. But sometimes (once in 7 days) I've got too big values for sda (between last and current ones) (5GB/second). sudo lshw -class disk *-disk description: ATA Disk product: SPCC Solid State physical id: 0.0.0 bus info: scsi@2:0.0.0 logical name: /dev/sda version: 08.2 serial: EB84075517B200427436 size: 111GiB (120GB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 logicalsectorsize=512 sectorsize=512 signature=d01f3b8e Also I've written the script for monitoring the statistics #!/bin/bash while (true) do str=`date`" $(cat /sys/block/sda/stat)" echo $str >> log.txt sleep 10; done And got this values Fr Jul 28 07:39:38 MSK 2017 2368466 475339 105223134 1362848 5753154 7692148 661424840 31319540 0 4790052 32687100 Fr Jul 28 07:39:48 MSK 2017 2368466 475339 105223134 1362848 5753170 7692160 661425104 31319548 0 4790060 32687108 Fr Jul 28 07:39:58 MSK 2017 2368466 475339 105223134 1362848 5753174 7692162 661425152 31319556 0 4790068 32687116 Fr Jul 28 07:40:08 MSK 2017 2369133 475339 105228750 1363380 5771079 7694395 706209560 31324696 0 4795572 32692780 Fr Jul 28 07:40:18 MSK 2017 2369133 475339 105228750 1363380 5771087 7694431 706209960 31324708 0 4795584 32692792 Fr Jul 28 07:40:28 MSK 2017 2369133 475339 105228750 1363380 5771091 7694433 706210008 31324716 0 4795592 32692800 Fr Jul 28 07:40:38 MSK 2017 2369133 475339 105228750 1363380 5771244 7694714 706213528 31325052 0 4795604 32693136 You can see that the difference (3,4 lines) is very big between 706209560 and 661425152, my ssd can read/write 250 Mb/sec, but not 5 Gb/sec. -- Best regards, Sergey Borisov