btrfs locking at 74% on 6.1.6

Well that's embarrassing.... I updated again to 6.1.6 final, and then when I went to look at the logs, realized I'd been reading out of an old download of the logs before.

I definitely was already on the latest:
ReadyNASOS!!version=6.1.6,time=1391111179,arch=x86_64

[2014/02/02 22:37:04] Factory default initiated by Frontview!
[2014/02/02 22:37:35] Defaulting to X-RAID2 mode, RAID level 5
[2014/02/02 22:37:58] Factory default initiated on ReadyNASOS 6.1.6.
[2014/02/09 00:03:34] Updated from ReadyNASOS 6.1.6 to 6.1.6.
[2014/02/17 00:23:18] Updated from ReadyNASOS 6.1.6 to 6.1.6.

Was able to immediately get it to do it again:
https://www.dropbox.com/s/ztvaeatfmrhngvk/Screenshot%202014-02-17%2002.38.10.png

I have been noticing similiar behavious myself where my load will spike up to 30 on 6.1.6, but since I never did a factory reset yet I have just begun the process of debugging what is wrong although I think my problem is related to installed apps though. I am impressed that my NAS is not crashing though.

Have you tried turning off all addons while copying?

One thing I noticed in regards to your top imagaes you provided is that Plex Media Server is running when you have these problems. I have also noticed my Plex Media Server seems to be high in the top list when I get these spikes. When I turn off addons like plexmediaserver and nzbget my load immediately goes down.

I switched to nzbget since I thought sabnzb was taking too much processing time when idle but it may also be causing problems. I also switched from using deluged to utorrent and utorrent is way better on my system load. I also created custom init.d scripts for alot of my apps that set ionice, nice and io scheduler class. For me I have narrowed down my misbehaving apps to either plexmediaserver, nzbget or bitcasa.

What version of Plex Media Server do you have installed?

I have version 0.9.9.2.374-aa23a69.

I think my problem is with nzbget now though. 98-99% of the time my load is fine. It just seems to be shooting up to a load of 20-30 every once in a while. Last time I just shut off nzbget and all went back to normal.

I wish there was a was to run iotop on this kernel. Maybe I will have to compile a version of the kernel myself :)

# iotop
Could not run iotop as some of the requirements are not met:
- Linux >= 2.6.20 with
  - I/O accounting support (CONFIG_TASKSTATS, CONFIG_TASK_DELAY_ACCT, CONFIG_TASK_IO_ACCOUNTING)

I'm running plex version="0.9.7.28.31-d1f35c1"

Interesting -- I shut down plex and have been transferring data for 20 minutes or so without a lockup.

Makes no sense to me -- especially as I'm not even transferring into a folder that plex monitors.

I'll continue transferring for a while, and then try turning plex back on and see if it locks up right away.

LogicX your Plex version is quite old. Might want to try a newer version.

Working on upgrading to a new version -- does look like mine is 9 months old or so.

I noticed the following in dmesg output:

INFO: task btrfs-transacti:2021 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
btrfs-transacti D 0000000100098c98 0 2021 2 0x00000000
ffff88001ba9dd20 0000000000000046 ffff880000000000 ffff88001ba9dfd8
ffff88001ba9dfd8 0000000000004000 ffff88003d46d910 ffff880039112990
0000000100000000 0000000000000001 00000000ffffffff ffff88003d402300
Call Trace:
[<ffffffff880a3e35>] ? __free_pages+0x25/0x30
[<ffffffff880d0052>] ? __free_slab+0xc2/0x190
[<ffffffff880ce984>] ? add_partial+0x24/0x80
[<ffffffff88879c6a>] schedule+0x3a/0x50
[<ffffffff8887a0b9>] schedule_timeout+0x1a9/0x210
[<ffffffff88063929>] ? prepare_to_wait+0x59/0x90
[<ffffffff882ddabb>] btrfs_commit_transaction+0x20b/0xa90
[<ffffffff88063b30>] ? abort_exclusive_wait+0xb0/0xb0
[<ffffffff882de9a5>] ? start_transaction+0x95/0x3f0
[<ffffffff882d5afd>] transaction_kthread+0x23d/0x260
[<ffffffff882d58c0>] ? btrfs_alloc_root+0x40/0x40
[<ffffffff88063339>] kthread+0x89/0x90
[<ffffffff8887cf34>] kernel_thread_helper+0x4/0x10
[<ffffffff880632b0>] ? kthread_worker_fn+0x140/0x140
[<ffffffff8887cf30>] ? gs_change+0xb/0xb

and I have a number of them:

root@Cabana:/var/log# dmesg |grep hung
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
root@Cabana:/var/log#