System Lockups with ScreenConnect 6.0.11622.6115 on CentOS 7

scottalanmiller

Here is the disk IOPS during the period:

# sar -b
Linux 3.10.0-327.10.1.el7.x86_64 (dny-lnx-sc) 	12/15/2016 	_x86_64_	(1 CPU)

12:00:02 AM       tps      rtps      wtps   bread/s   bwrtn/s
12:10:02 AM     37.78     35.51      2.26   2141.75    950.39
12:20:02 AM     60.72     59.03      1.69    740.81    459.02
12:30:03 AM     49.76     44.11      5.65   1478.99   1278.96
12:40:02 AM      4.00      0.10      3.91      6.73     94.01
12:50:02 AM      1.01      0.00      1.01      0.00     18.47
01:00:02 AM      2.50      0.01      2.49      0.07     47.46
01:10:02 AM      6.86      4.90      1.96    277.61     48.09
01:20:01 AM      1.09      0.08      1.01      0.70     16.29
01:30:02 AM      1.00      0.07      0.94      0.54     15.46
01:40:02 AM      1.48      0.34      1.14     17.05     22.31
01:50:01 AM      1.06      0.08      0.98      0.80     16.44
02:00:02 AM      0.95      0.07      0.88      0.52     14.62
02:10:02 AM      2.72      1.71      1.01    127.08     19.63
02:20:02 AM      1.43      0.40      1.03     19.09     16.96
02:30:01 AM      1.13      0.09      1.04      0.71     17.83
02:40:01 AM      1.02      0.07      0.95      0.54     15.96
02:50:02 AM      1.60      0.45      1.15     22.49     22.96
03:00:02 AM      1.14      0.07      1.07      0.52     18.29
03:10:02 AM      1.87      0.87      0.99     23.37     17.08
03:20:02 AM      3.42      1.64      1.78    105.42     42.86
03:30:01 AM      1.48      0.05      1.43      0.41     29.83
03:40:01 AM      1.67      0.44      1.23      8.28     22.61
03:50:02 AM      0.87      0.04      0.83      0.29     14.34
04:00:02 AM      0.59      0.04      0.55      0.74      9.05
04:10:02 AM      1.26      0.23      1.03      1.85     20.58
04:20:03 AM      2.61      1.76      0.84    125.26     23.16
04:30:02 AM      1.56      0.51      1.06     30.12     17.36
04:40:01 AM      1.03      0.09      0.94      0.73     15.92
04:50:02 AM      1.10      0.11      0.99      0.89     16.81
05:00:01 AM      1.03      0.08      0.95      0.63     15.98
05:10:02 AM      2.18      1.03      1.16     19.42     20.66
05:20:02 AM      4.03      2.23      1.80     97.92     28.06
05:30:01 AM      1.33      0.39      0.95      4.33     15.65
05:40:02 AM      1.11      0.29      0.82     31.88     13.22
05:50:02 AM      0.94      0.04      0.90      1.75     14.25
06:00:02 AM      0.92      0.11      0.81      7.09     12.71
06:10:02 AM      3.43      2.45      0.98    190.42     16.55
06:20:02 AM      0.76      0.01      0.75      0.06     11.95
06:30:01 AM      0.78      0.00      0.78      0.00     12.62
06:40:02 AM      0.78      0.00      0.78      0.00     11.97
06:50:02 AM      0.83      0.01      0.82      0.26     12.23
07:00:04 AM     18.36     11.59      6.77    938.93    372.35
07:10:02 AM      8.82      7.30      1.52    378.69     29.30
07:20:02 AM      0.81      0.00      0.81      0.01     12.34

07:20:02 AM       tps      rtps      wtps   bread/s   bwrtn/s
07:30:01 AM      0.78      0.00      0.78      0.00     11.55
07:40:02 AM      0.78      0.00      0.78      0.00     11.72
07:50:02 AM      0.93      0.12      0.81     22.45     12.71
08:00:02 AM      0.81      0.06      0.75      4.49     11.00
08:10:02 AM      5.67      4.84      0.83    166.27     13.62
Average:         5.09      3.73      1.35    142.61     81.15

08:11:58 AM       LINUX RESTART

08:20:01 AM       tps      rtps      wtps   bread/s   bwrtn/s
08:30:01 AM    162.30    151.14     11.15  12920.88   2905.10
08:40:02 AM    129.66    120.51      9.15   7687.04   1985.90
08:50:01 AM     10.27      6.22      4.05    356.26    212.99
09:00:01 AM      5.04      1.12      3.92     37.33    104.27
09:10:01 AM      9.50      6.04      3.46    489.18    493.55
09:20:01 AM      5.15      1.93      3.22     31.62     88.30
09:30:02 AM      2.77      0.03      2.74      1.36     75.94
09:40:01 AM      3.22      0.06      3.16      1.24     87.54
09:50:01 AM      3.14      0.28      2.87      8.37     80.30
10:00:01 AM      7.41      4.23      3.18    162.67     89.22
10:10:02 AM      7.35      4.22      3.13    416.22    113.30
10:20:01 AM      5.79      2.59      3.20    104.94     89.60
10:30:01 AM      3.10      0.02      3.08      1.90     88.28
10:40:01 AM     15.26     12.06      3.20    637.15     92.53
Average:        25.61     21.40      4.21   1574.71    451.49

scottalanmiller

HTOP when things are healthy:

0_1481816777214_Screenshot from 2016-12-15 10-46-05.png

scottalanmiller

TOP when healthy:

0_1481816822884_Screenshot from 2016-12-15 10-46-51.png

scottalanmiller

GLANCES when healthy:

0_1481816869193_Screenshot from 2016-12-15 10-47-45.png

scottalanmiller

We know that the process that takes the system resources is mono which is screenconnects parent container.

hobbit666

Looks like i'm running the same version:-

On CentOS7 ( I think it's all up to date with patches etc)

Not seeing this problem.
Running on XenServer 7 - 2vCPU 2GB RAM 40GB HD Space

scottalanmiller

@hobbit666 take a look at your SAR output, any chance that you have one threading engine hitting the wall and one that is not?

scottalanmiller

We are resizing the instance up to 2 vCPU and 2GB RAM right now to see what happens with more resources available at ScreenConnect support's request. But it is not using the resources available to it now, we are afraid of masking the issue and getting the system limping along rather than fixing it.

gjacobse

@DustinB3403 said in System Lockups with ScreenConnect 6.0.11622.6115 on CentOS 7:

Any chance you can clone this VM, and downgrade the SC version to the previous version. And monitor both, putting them side by side?

No, can't downgrade that easily as the Client version would be different and not likely to re-sync

scottalanmiller

Resized and the issue remains. Look at that CPU load for an idle box!!

0_1481817709995_Screenshot from 2016-12-15 11-01-22.png

hobbit666

Sorry @scottalanmiller i'm a Linux newb

How do I run the SAR stuff?

gjacobse

@hobbit666 said in System Lockups with ScreenConnect 6.0.11622.6115 on CentOS 7:

Sorry @scottalanmiller i'm a Linux newb

How do I run the SAR stuff?

If it is installed, form CLI just run

sar

gjacobse

@gjacobse said in System Lockups with ScreenConnect 6.0.11622.6115 on CentOS 7:

@hobbit666 said in System Lockups with ScreenConnect 6.0.11622.6115 on CentOS 7:

Sorry @scottalanmiller i'm a Linux newb

How do I run the SAR stuff?

If it is installed, form CLI just run
sar

If it is not installed

$ yum install sysstat

gjacobse

Example of $ sar

$ sar
Linux 3.10.0-327.10.1.el7.x86_64 (dny-lnx-sc)   12/15/2016      _x86_64_        (2 CPU)

10:56:35 AM       LINUX RESTART

11:00:02 AM     CPU     %user     %nice   %system   %iowait    %steal     %idle
11:10:01 AM     all     22.30      0.00      0.85      0.16      3.05     73.64
Average:        all     22.30      0.00      0.85      0.16      3.05     73.64

Or as above from @scottalanmiller with $ sar -b

hobbit666

This is all i'm getting from SAR

[root@screenconnect6 ~]# sar
Linux 3.10.0-327.28.3.el7.x86_64 (screenconnect6) 15/12/16 x86_64 (2 CPU)

16:20:43 LINUX RESTART

hobbit666

@scottalanmiller said in System Lockups with ScreenConnect 6.0.11622.6115 on CentOS 7:

Resized and the issue remains. Look at that CPU load for an idle box!!

How do you get that pretty picture??

Funny I was about to start a thread about tuning Linux systems for resources so I can free some up for more VM's

scottalanmiller

@hobbit666 said in System Lockups with ScreenConnect 6.0.11622.6115 on CentOS 7:

This is all i'm getting from SAR

[root@screenconnect6 ~]# sar
Linux 3.10.0-327.28.3.el7.x86_64 (screenconnect6) 15/12/16 x86_64 (2 CPU)

16:20:43 LINUX RESTART

Takes ten minutes to accumulate the first line of data.

scottalanmiller

@hobbit666 said in System Lockups with ScreenConnect 6.0.11622.6115 on CentOS 7:

@scottalanmiller said in System Lockups with ScreenConnect 6.0.11622.6115 on CentOS 7:

Resized and the issue remains. Look at that CPU load for an idle box!!

How do you get that pretty picture??

Command is htop, it's in the EPEL. Then I just screenshot it. It's the default terminal on Ubuntu 16.10.

hobbit666

OK so i'll leave my VM running over night as i'll be heading home soon.

I've put a sticky note on my monitor to remind me to run the commands and post screenshots

scottalanmiller

Tagging @LG-at-ConnectWise