Arch Linux

mnx

Member

From: Bochum, Germany

Registered: 2012-12-09

Posts: 3

Unresponsive processes while running backup on external USB 3.0 disk

On my home server "rsnapshot" backups are triggered via crond. Backups are copied to a "Western Digital My Book Essential USB3.0". This sometimes result in a problem. Symptoms are never-ending processes (in this case: rsnapshot), running with high CPU load. Sometimes those processes consume so much CPU that it's hardly possible to control the system (even login does take minutes to finish). When trying to kill those processes they do not react neither on a kill nor on a kill -9. Unmounting the device was not possible. When manually pulling the USB cable (yes I know, I should not do that) a kernel trace was dumped into dmesg/journal (see below).

http://codepad.org/GE2rn89E

My question:
Does this look like a kernel/driver bug or more like a faulty drive?
Do the stack traces occur from unplugging the cable before unmounting? I tried this on another machine and there was no such stack trace.
Where do all those "rcu_preempt" events come from? They start appearing right after the 04:00:00 hourly backup (or in between). Can there be a relation? I only find IPv6 related stuff when searching for "rcu_preempt" issues.

lspci:

00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 05)
00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05)
00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b5)
00:1c.3 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 4 (rev b5)
00:1c.5 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 6 (rev b5)
00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 05)
00:1f.0 ISA bridge: Intel Corporation H61 Express Chipset Family LPC Controller (rev 05)
00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family SATA AHCI Controller (rev 05)
00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 05)
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)
03:00.0 USB controller: ASMedia Technology Inc. ASM1042 SuperSpeed USB Host Controller

uname -rmv:

3.14.4-1-ARCH #1 SMP PREEMPT Tue May 13 16:41:39 CEST 2014 x86_64

Any help is appreciated, thanks in advance.

Cheers

Last edited by mnx (2014-05-26 21:02:32)

midixinga

Member

Registered: 2014-01-18

Posts: 193

Re: Unresponsive processes while running backup on external USB 3.0 disk

I guess, it's a normal behavior of rsync. Take a look at ionice

gedgon

Member

From: Poland

Registered: 2011-01-27

Posts: 95

Re: Unresponsive processes while running backup on external USB 3.0 disk

What you described is rather extreme (so check also your HDD for bad sectors), but give it a try:
https://wiki.archlinux.org/index.php/Sy … ual_memory
https://wiki.archlinux.org/index.php/Pe … ge_devices