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I am using LUKS encrypted BTRFS partitions on a couple of systems (all with SSDs), but on one I am facing issues with `btrfs-cleaner` running forever, and utilizing one core of that system.
The problem is not too easy to pinpoint, since I also cannot trigger it. After rebooting the system, everything looks normal. I can create and delete snapshots (I'm using snapper typically) without any issues. Also scrubbing works without any problems or errors. This normal state can last for hours (maybe even days), but at some point I am getting this in `top`
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
532 root 20 0 0 0 0 R 100.0 0.0 3068:27 btrfs-cleaner
and this in `iotop`
TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND
532 be/4 root 0.00 B/s 2.26 G/s 0.00 % 0.00 % [btrfs-cleaner]
Some online research seems to indicate that it could maybe be related to btrfs quotas or that the drive is failing. However, quotas aren't enabled, and the drive seems fine (I think):
# smartctl -A /dev/sda
smartctl 7.0 2018-12-30 r4883 [x86_64-linux-5.0.13-arch1-1-ARCH] (local build)
Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF READ SMART DATA SECTION ===
SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
5 Reallocated_Sector_Ct 0x0033 100 100 010 Pre-fail Always - 0
9 Power_On_Hours 0x0032 097 097 000 Old_age Always - 14304
12 Power_Cycle_Count 0x0032 099 099 000 Old_age Always - 26
177 Wear_Leveling_Count 0x0013 099 099 000 Pre-fail Always - 14
179 Used_Rsvd_Blk_Cnt_Tot 0x0013 100 100 010 Pre-fail Always - 0
181 Program_Fail_Cnt_Total 0x0032 100 100 010 Old_age Always - 0
182 Erase_Fail_Count_Total 0x0032 100 100 010 Old_age Always - 0
183 Runtime_Bad_Block 0x0013 100 100 010 Pre-fail Always - 0
187 Uncorrectable_Error_Cnt 0x0032 100 100 000 Old_age Always - 0
190 Airflow_Temperature_Cel 0x0032 076 066 000 Old_age Always - 24
195 ECC_Error_Rate 0x001a 200 200 000 Old_age Always - 0
199 CRC_Error_Count 0x003e 100 100 000 Old_age Always - 0
235 POR_Recovery_Count 0x0012 099 099 000 Old_age Always - 16
241 Total_LBAs_Written 0x0032 099 099 000 Old_age Always - 17939834361
The drive is a Samsung SSD 850 EVO 250GB and I am using this in `/etc/fstab`:
UUID=50e7187f-5619-43ef-9625-a8084bca51c1 / btrfs rw,noatime,compress=lzo,ssd,discard,space_cache,subvol=@ROOT 0 0
UUID=50e7187f-5619-43ef-9625-a8084bca51c1 /.snapshots btrfs rw,noatime,compress=lzo,ssd,discard,space_cache,subvol=@SNAPSHOTS 0 0
UUID=50e7187f-5619-43ef-9625-a8084bca51c1 /var btrfs rw,noatime,compress=lzo,ssd,discard,space_cache,subvol=@VAR 0 0
Any idea on resolving this issue or even triggering the issue in order to find a solution is highly appreciated.
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Check dmesg if you see any failures.
FWIW Samsung SSDs are notorious for not playing well with power management, try if you see an improvement by switching to max_performance: https://wiki.archlinux.org/index.php/Po … Management
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Thanks for your response, V1del!
Check dmesg if you see any failures.
dmesg did not show anything. Sorry, I forgot to mention that.
FWIW Samsung SSDs are notorious for not playing well with power management, try if you see an improvement by switching to max_performance: https://wiki.archlinux.org/index.php/Po … Management
I will enable this right now! Let us see what is happening. Thanks!
[edit]
Actually, it was on max_performance already.
$ cat /sys/class/scsi_host/host*/link_power_management_policy
max_performance
max_performance
max_performance
max_performance
max_performance
max_performance
max_performance
max_performance
max_performance
[/edit]
Last edited by tinux (2019-05-10 12:23:59)
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What is 'btrfs-cleaner', and what does it do? It's not provided by any Arch package, and isn't listed on the wiki.
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What is 'btrfs-cleaner', and what does it do? It's not provided by any Arch package, and isn't listed on the wiki.
It does not come with any package. I assume it is a kernel process.
As to its function, where I am also not sure, I think it is involved in removing snapshots, but I do not know if it is limited to that.
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Looks like it's a feature of BTRFS.
Prevailing suggestion seems to be to disable quotas:
btrfs quota disable /
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Looks like it's a feature of BTRFS.
Prevailing suggestion seems to be to disable quotas:
btrfs quota disable /
That is also what I found when I searched online for this issue. However, as I said in the initial post, quotas are disabled.
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I switched to linux-zen and I'm having the same issue. I might try the default kernel next time I reboot. Was curious if you're using an alternative kernel and if there's any link to that.
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emphire, this topic is a year old and the OP has not been back to the forum for several months (and has apparently abandoned this topic). Please do not necrobump; instead, start your own topic and refer back to this one if you think it applies.
Closing this old topic. tinux, if you come back and want this topic reopened, please use the Report link.
How to post. A sincere effort to use modest and proper language and grammar is a sign of respect toward the community.
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