Memory (MongoDB)



  • I know this issue has been raised before, but how is the mem-usage supposed to be for NodeBB?

    I have a 500MB Digital Ocean droplet, only NodeBB and MongoDB running, and I got 61MB free with no-one but me and my 59 posts in the forum atm, and the MongoD has been running for about three weeks.

    Initially I thought MongoDB was the hog, but I am now bit amazed that it's NodeBB. Not sure what I was expecting, but still a but puzzled about that...

    $> free -m
                          total        used        free      shared  buff/cache   available
    Mem:            488         302          59           0         127         154
    Swap:             0           0           0
    
    $> top
    PID USER      PR  NI    VIRT    RES    SHR S %MEM %CPU     TIME+ COMMAND      
    2282 gnimmelf  20   0 1350308 180760  16624 S 36.1  0.0   0:16.46 nodejs       
    2024 gnimmelf  20   0  955644  40172  10268 S  8.0  0.0   0:01.00 nodejs       
    1269 mongodb   20   0  268956  34404    364 S  6.9  1.3   0:17.84 mongod 
    

    -Both nodejs's are NodeBB...

    If I start with ./nodebb dev, I'm left with 9MB free, which kills it when I install plugins in dev mode...

    Maybe we could spec out some aprox. minimum requirements for NodeBB, pref in conjunction with DB setups (MongoDB, I hate reading your documentation!)?

    If I open up this forum for the intended people, around 200, it will probably die quite often, I can assume, even though I doubt there will bee too much traffic.

    Per now my only option is to resize the droplet to $10 or $20, which is doable, but not preferable to technical trimming of any kind =)

    Please advice, and I'll be happy to help.

    /Cheers


  • Plugin & Theme Dev

    @Flemming-Hansen you should setup swap space. I have 3 nodebb instances running on a $5 droplet without problems although they are demo instances with very low traffic.


  • Admin

    As @pichalite says, you must set up swap, or else your OS might OOM and terminate Mongo :laughing:

    A 512mb server will support a NodeBB forum just fine, and the OS won't 'free up' memory unless it's actually needed, so free -m will show higher memory utilisation even though not that much memory is actually being used.



  • Agree, but D.O. does not reccomend swap on their SSDs, due to to hardware degradation...
    Maybe not such an issue with my low usage?

    Just discovered #define ENOMEM 12 /* Out of memory */ =)


  • Gamers

    @Flemming-Hansen said in Memory (MongoDB):

    Agree, but D.O. does not reccomend swap on their SSDs, due to to hardware degradation...
    Maybe not such an issue with my low usage?

    Just discovered #define ENOMEM 12 /* Out of memory */ =)

    If you're concerned about hardware degradation, set up swap and set the swapiness value to 1! Then no process will get out of memory while no swap will be used if it is not needed.



  • I also use DO 512 droplet, my stats:

    >$ free -m
                  total        used        free      shared  buff/cache   available
    Mem:            488         309           9           0         169         150
    Swap:          2047         349        1698
    
    >$ top
    
    Tasks: 125 total,   1 running, 124 sleeping,   0 stopped,   0 zombie
    %Cpu(s): 29,5 us,  3,5 sy,  0,0 ni, 65,1 id,  1,3 wa,  0,0 hi,  0,3 si,  0,2 st
    KiB Mem :   500240 total,    10380 free,   326400 used,   163460 buff/cache
    KiB Swap:  2097148 total,  1658900 free,   438248 used.   144060 avail Mem 
    
      PID USER   PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND                                                                                                  
    26782 user   20   0 1742332 242332   6188 S  6,7 48,4 291:51.62 nodejs                                                                                                   
    31669 user   20   0   43612   3800   3204 R  6,7  0,8   0:00.01 top                                                                                                      
        1 root   20   0   37888   3316   2192 S  0,0  0,7   0:15.36 systemd                         
    

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    Users 2,842
    posts 116,070


  • Admin

    @Flemming-Hansen said in Memory (MongoDB):

    Agree, but D.O. does not reccomend swap on their SSDs, due to to hardware degradation...
    Maybe not such an issue with my low usage?

    Yes, that is true... setting swap up on an SSD is potentially "not as good", only because you're shuttling data back and forth from SSD and RAM, increasing the writes to the SSD... but that said, they still do have an article about configuring it... :wink:



  • @alff0x1f excellent! Thank you very much for those printouts. Swap it is, then =)


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