All of a sudden SSH is really lagging/slow.

Mar

After coming back to my mirror after a month or so of not touching it as I’ve been quite happy with the set up I’ve noticed whenever im in SSH that its extremely slow. To the point of it becoming very difficult to even type on the command line let alone use nano.

I’m wondering if anyone has any ways I could troubleshoot why this is happening. I’ve not moved the physical Pi or changed anything. It used to run absolutely perfectly.

Any help would be greatly appreciated.

yawns

I know this is the typical IT support question, but did you reboot the raspberry and check if this lag still is the case after rebooting?

Mar

@yawns thanks for the reply. Yes I’ve restarted it many-many times in the last few days. Valid question.

yawns

Ok. Is your pi connected with wifi or lan?

You could try this:

sudo nano /etc/ssh/sshd_config, then add UseDNS no to the file and save your changes. Afterwards reboot your pi or run sudo service ssh restart

Snille

@Mar If you get in to SSH, check if you have a HUGE file called “core” in your MagicMirror directory. If you do, delete it. I have had the same issue, EVERYTHING get’s slow and eventually you cant do anything. I noticed the file on my second install (again) and deleted it before it died. Now I’m trying to find how this file get’s created. It should not be there.

strawberry 3.141

@Snille does a module create this file? I don’t have a file called core in my mm directory

Mar

Thanks for the tips everyone.
@yawns I’m connected via wifi and in the same room as the router, nothing has changed here. I’ve attempted to add the UseDNS=no but it didnt seem to change the major lag im experiencing. i.e i type and it takes a few seconds for it to show up on the command line. But when I tried ‘UseDNS no’ (as this seemed to be the syntax in the file) it seemed to be a little speedier upon the next reboot! Not near as fast as it was a few weeks back but now i can get in and navigate around etc. Thanks!

I wonder if there is anything else that could be slowing it down, how does the UsDNS command speed things up like it did?

@Snille i’ve done an ls -alh in a few of the directories and have no large file name core. Would there be any other temp/log type of files that could be causing a slowdown?

Snille

@strawberry-3.141 I don’t know yet. I just rebooted my mirror now and got it back again. I’m trying to figuring it out.
Here is my MagicMirror dir after this reboot…
The file is there again… :/

drwxr-xr-x  16 pi pi      4096 Mar 22 11:06 .
drwxr-xr-x  21 pi pi      4096 Mar 22 11:08 ..
-rw-r--r--   1 pi pi     11172 Mar 21 13:37 CHANGELOG.md
drwxr-xr-x   2 pi pi      4096 Mar 21 13:52 config
-rw-------   1 pi pi 574697472 Mar 22 11:07 core
drwxr-xr-x   2 pi pi      4096 Mar 21 13:37 css
-rw-r--r--   1 pi pi       266 Mar 21 13:37 docker-entrypoint.sh
-rw-r--r--   1 pi pi       378 Mar 21 13:37 Dockerfile
-rw-r--r--   1 pi pi       964 Mar 21 13:37 .dockerignore
-rw-r--r--   1 pi pi       132 Mar 21 13:37 .eslintignore
-rw-r--r--   1 pi pi       319 Mar 21 13:37 .eslintrc.json
drwxr-xr-x  20 pi pi      4096 Mar 21 13:37 fonts
drwxr-xr-x   8 pi pi      4096 Mar 22 11:09 .git
drwxr-xr-x   2 pi pi      4096 Mar 21 13:37 .github
-rw-r--r--   1 pi pi       915 Mar 21 13:37 .gitignore
-rw-r--r--   1 pi pi      2173 Mar 21 13:37 Gruntfile.js
-rw-r--r--   1 pi pi      2337 Mar 21 13:37 index.html
drwxr-xr-x   3 pi pi      4096 Mar 21 13:37 installers
drwxr-xr-x   2 pi pi      4096 Mar 21 13:37 js
-rw-r--r--   1 pi pi       271 Mar 21 13:37 jsconfig.json
-rw-r--r--   1 pi pi      1118 Mar 21 13:37 LICENSE.md
drwxr-xr-x  27 pi pi      4096 Mar 22 08:40 modules
drwxr-xr-x 561 pi pi     20480 Mar 22 10:55 node_modules
-rw-r--r--   1 pi pi      1789 Mar 21 13:37 package.json
-rw-r--r--   1 pi pi     11431 Mar 21 13:37 README.md
-rw-r--r--   1 pi pi       141 Mar 21 13:37 run-start.sh
drwxr-xr-x   2 pi pi      4096 Mar 21 13:37 serveronly
-rw-r--r--   1 pi pi       478 Mar 21 13:37 .snyk
drwxr-xr-x   2 pi pi      4096 Mar 21 13:37 splashscreen
-rw-r--r--   1 pi pi       126 Mar 21 13:37 .stylelintrc
drwxr-xr-x   6 pi pi      4096 Mar 21 13:37 tests
drwxr-xr-x   2 pi pi      4096 Mar 21 13:37 translations
-rw-r--r--   1 pi pi       229 Mar 21 13:37 .travis.yml
drwxr-xr-x   3 pi pi      4096 Mar 21 23:24 vendor

strawberry 3.141

@Snille disable all modules delete this file and put only one module step by step to check what is creating this file. Can you open that file in an editor to get more details?

@Mar which modules you’re using? how about the cpu usage?

Snille

@strawberry-3.141 That’s what I’m doing right now… :)

yawns

@Mar
Thanks for the feedback. I will change my post and remove the =, so others won’t run into the same mistake.

Mar

@strawberry-3.141 My cpu usage (using top) after the pi has booted up stays around 3-5% (using the top command raises this a bit). And memory usage doesnt seem out of control either.

top - 10:36:12 up 43 min,  3 users,  load average: 0.14, 0.12, 0.11
Tasks: 107 total,   1 running, 100 sleeping,   6 stopped,   0 zombie
%Cpu(s):  4.7 us,  1.0 sy,  0.0 ni, 93.9 id,  0.0 wa,  0.0 hi,  0.3 si,  0.0 st
KiB Mem:    445084 total,   340880 used,   104204 free,    26108 buffers
KiB Swap:   102396 total,        0 used,   102396 free.   159376 cached Mem

  PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND                                      
  611 pi        20   0  205560  77592  42308 S  3.3 17.4   1:35.69 midori                                       
 3581 pi        20   0    5232   2596   2160 R  1.6  0.6   0:00.38 top                                          
   60 root      20   0       0      0      0 S  0.3  0.0   0:02.04 kworker/0:2                                  
  594 root      19  -1  154840  47040  21040 S  0.3 10.6   0:16.78 Xorg                                         
 3241 pi        20   0   11940   3440   2768 S  0.3  0.8   0:00.89 sshd                                         
    1 root      20   0    5308   3776   2736 S  0.0  0.8   0:07.32 systemd                                      
    2 root      20   0       0      0      0 S  0.0  0.0   0:00.01 kthreadd                                     
    3 root      20   0       0      0      0 S  0.0  0.0   0:01.17 ksoftirqd/0

Im using the following modules.

profileswitcher, buttons, clock, calendar, compliments, current weather, weather forecast, wunderlist, newsfeed, calendar monthly, tube status, and system stats.

Snille

@strawberry-3-141 Hmm… It does not seam to be any module doing it… I’m thinking it’s a “core-dump”, I noticed when restarting that it took a long time before it actually restarted. I’m guessing something did not close down properly, then the memory (or something) is dumped down to a file… Now it’s not happening any longer… Reboots normally. Only thing is that I lost my pm2 autostart of the mirror for some reason (had to do a pm2 startup and run the “setup” command sudo env PATH=$PATH:/usr/bin /usr/lib/node_modules/pm2/bin/pm2 startup systemd -u pi --hp /home/pi again… And now it starts normally again… No core file after reboots, all modules back again… Darn! :)

strawberry 3.141

@Mar does the ssh speedup when you shut down the mirror?

Mar

@strawberry-3.141 Oh wow! Ran a pm2 stop mm and the ssh went back to exactly how it used to be. No lag at all and can use nano on the config file with zero lag (could even mouse wheel scroll perfectly).

Then starting MM back up (pm2 start mm) it seems to maintain the quick ssh speed. Upon a full reboot though it seems to get back to being slightly slower.

Snille

Just got myself a “core”-file again in the MM root. :) I’m now sure it’s because Electron is crashing. So, it’s probably a memory dump. Still don’t really know why Electron is crashing. It’s not crashing all the time. Just sometimes. But then, I do have lot’s of modules going… :)