"man btrfs-check" gives the documentation.
I have never used the check command before. My internet M2 2880 nvme SSD was unmounted, so why not? Here are the results.
root@jerry-hp17cn1xxx:~# btrfs check -p --mode lowmem /dev/nvme0n1p1
No errors found. That's nice. I don't need to run the "--repair" option.
The "-p" option showed the progress as it occurred and gave the output captured above.
I have only 16GB of RAM so I used the "--mode lowmem" option to keep the process from running out of RAM.
Then I decided to do a check data sum.
root@jerry-hp17cn1xxx:~# btrfs check -p --mode lowmem --check-data-csum /dev/nvme0n1p1
The Psensor graph showed what happened.
The first spike is when the command began. The second spike is when the check summing began. The nvme ctl chip shot up to 57C and then began falling off. At the same time, the nvme VNAND chip began climbing and flatlined at 46C.
Each vertical line is 5 minutes. So the graph shows VNAND at 46C for 18 minutes. It's now an addition a 30 minutes later and VNAND is still at 46C, so what ever the check sum triggered it has been going on for 48 minutes. I decided to mount the nvme and see if that had any effect. Immediately when I mounted it the VNAND temp dropped to 30C. Strange. If I had mounted it earlier, perhaps even as CTL reached 30C, VNAND may have dropped to 30C as well.
But, since both checks showed no errors, there was no need to use the "--repair" option.
I have never used the check command before. My internet M2 2880 nvme SSD was unmounted, so why not? Here are the results.
root@jerry-hp17cn1xxx:~# btrfs check -p --mode lowmem /dev/nvme0n1p1
Code:
[FONT=monospace]Opening filesystem to check... Checking filesystem on /dev/nvme0n1p1 UUID: 4ea5991d-7da6-4387-907d-acef20d047de [1/7] checking root items (0:00:00 elapsed, 702978 items checked) [2/7] checking extents (0:01:03 elapsed, 310795 items checked) [3/7] checking free space cache (0:00:00 elapsed, 166 items checked) [4/7] checking fs roots (0:01:53 elapsed, 60210 items checked) [5/7] checking csums (without verifying data) (0:00:00 elapsed, 112083 items checked) [6/7] checking root refs done with fs roots in lowmem mode, skipping [7/7] checking quota groups skipped (not enabled on this FS) found 164358307840 bytes used, [COLOR=#e74c3c]no error found[/COLOR] total csum bytes: 159202256 total tree bytes: 1294565376 total fs tree bytes: 1049591808 total extent tree bytes: 61440000 btree space waste bytes: 199230567 file data blocks allocated: 191000690688 referenced 188350816256 root@jerry-hp17cn1xxx:~# [/FONT]
The "-p" option showed the progress as it occurred and gave the output captured above.
I have only 16GB of RAM so I used the "--mode lowmem" option to keep the process from running out of RAM.
Then I decided to do a check data sum.
root@jerry-hp17cn1xxx:~# btrfs check -p --mode lowmem --check-data-csum /dev/nvme0n1p1
Code:
Opening filesystem to check... Checking filesystem on /dev/nvme0n1p1 UUID: 4ea5991d-7da6-4387-907d-acef20d047de [1/7] checking root items (0:00:00 elapsed, 702978 items checked) [2/7] checking extents (0:01:10 elapsed, 310795 items checked) [3/7] checking free space cache (0:00:00 elapsed, 166 items checked) [4/7] checking fs roots (0:01:54 elapsed, 60210 items checked) [5/7] checking csums against data (0:01:25 elapsed, 112083 items checked) [6/7] checking root refs done with fs roots in lowmem mode, skipping [7/7] checking quota groups skipped (not enabled on this FS) found 164358307840 bytes used, [COLOR=#e74c3c][B]no error found[/B][/COLOR] total csum bytes: 159202256 total tree bytes: 1294565376 total fs tree bytes: 1049591808 total extent tree bytes: 61440000 btree space waste bytes: 199230567 file data blocks allocated: 191000690688 referenced 188350816256 root@jerry-hp17cn1xxx:~#
The first spike is when the command began. The second spike is when the check summing began. The nvme ctl chip shot up to 57C and then began falling off. At the same time, the nvme VNAND chip began climbing and flatlined at 46C.
Each vertical line is 5 minutes. So the graph shows VNAND at 46C for 18 minutes. It's now an addition a 30 minutes later and VNAND is still at 46C, so what ever the check sum triggered it has been going on for 48 minutes. I decided to mount the nvme and see if that had any effect. Immediately when I mounted it the VNAND temp dropped to 30C. Strange. If I had mounted it earlier, perhaps even as CTL reached 30C, VNAND may have dropped to 30C as well.
But, since both checks showed no errors, there was no need to use the "--repair" option.
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