bcache (bcache0 in this sample) ioutil goes to 100% and avgqu-sz also gets affected. Bcache slaves don't get affected, but does affect storage performance.
See excerpt (bcache0):
http://pastebin.ubuntu.com/23948463/
* Bcache blocks are running Ceph OSDs.
* HW is PowerEdge R730xd
* Kernel version is: 4.4.0-51-generic
* Ubuntu 14.04.5 LTS
* bcache-tools 1.0.7-1~14.04.1
Please let me know if you would need further detail.
---
AlsaDevices:
total 0
crw-rw---- 1 root audio 116, 1 Feb 7 12:45 seq
crw-rw---- 1 root audio 116, 33 Feb 7 12:45 timer
AplayDevices: Error: [Errno 2] No such file or directory
ApportVersion: 2.14.1-0ubuntu3.21
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
DistroRelease: Ubuntu 14.04
IwConfig: Error: [Errno 2] No such file or directory
Lsusb:
Bus 002 Device 002: ID 8087:8002 Intel Corp.
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 413c:a001 Dell Computer Corp. Hub
Bus 001 Device 002: ID 8087:800a Intel Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Dell Inc. PowerEdge R730xd
Package: linux (not installed)
PciMultimedia:
ProcEnviron:
TERM=screen
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB:
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-51-generic root=UUID=dc9574d7-cd8b-4db0-af85-db73ea17df65 ro console=tty0 console=ttyS0,115200n8
ProcVersionSignature: Ubuntu 4.4.0-51.72~14.04.1-generic 4.4.30
RelatedPackageVersions:
linux-restricted-modules-4.4.0-51-generic N/A
linux-backports-modules-4.4.0-51-generic N/A
linux-firmware 1.127.22
RfKill: Error: [Errno 2] No such file or directory
Tags: trusty uec-images
Uname: Linux 4.4.0-51-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:
_MarkForUpload: True
dmi.bios.date: 08/28/2014
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.0.4
dmi.board.name: 0H21J3
dmi.board.vendor: Dell Inc.
dmi.board.version: A04
dmi.chassis.type: 23
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.0.4:bd08/28/2014:svnDellInc.:pnPowerEdgeR730xd:pvr:rvnDellInc.:rn0H21J3:rvrA04:cvnDellInc.:ct23:cvr:
dmi.product.name: PowerEdge R730xd
dmi.sys.vendor: Dell Inc.
This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:
apport-collect 1662573
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.