Re: SO kills ns-ldapd because of memory usage

Ludwig Krispenz <lkrispen@xxxxxxxxxx> · Fri, 23 Nov 2012 11:35:56 +0100



    Hi,

      
      from the data you show, the server process should never reach
      11GB, so It could be that you run into a memory leak. Could you
      monitor process size growth ?

      Start the server, prime the caches for all backends and monitor
      process growth, eg running regular 

      ps -o 'vsz,rss' <pid>

      See how fast the process grows, if it is steadily or if there is a
      pattern and you can relate it to some cliend load.

      
      Regards,

      Ludwig

      
      On 11/22/2012 02:33 PM, Moisés Barba Pérez wrote:

    
      Hi,
      

      I have been searching for memory usage in the server. This
        are the results:
      

      389-ds
          1.2.5 in a CentOS 5.5 64bits 4GB ram and 6GB swap

      
      * The ns-slapd proccess reaches 11GB of virtual memory. pmap
        shows multiple [anon] using the bigger part of that 11G virtual
        memory. I think the [anon] are memory reservation from malloc
        and mmap but I don't know what call this.
      

      * Looking for cachememsize using this search for one of the
        database
      

        ldapsearch -H ldaps://localhost -x
            -LLL -b "cn=monitor,cn=o_xxxx,cn=ldbm
            database,cn=plugins,cn=config" -D "cn=Directory Manager" -W
            "(objectclass=*)" | grep entrycache
        Enter LDAP Password: 
        entrycachehitratio: 99

          
        currententrycachesize: 49973691
        maxentrycachesize: 125829120
        currententrycachecount: 6521
        maxentrycachecount: -1
      
      
      I have prime that database searching all entries with -> ldapsearch -H ldaps://localhost -x -LLL -b
          "o=cabu,dc=sacyl,dc=es" -D "cn=directory manager" -W
          "(objectclass=*)" 1.1 | grep dn: | wc -l 
      The result is 7610 entries in that database, so looking the
        monitor again:
      

        currententrycachesize: 59315175
        maxentrycachesize: 125829120
        currententrycachecount: 7611
      
      
      The id2entry.db4 for that database is 59539456 so I guess I
        can reduce the cachememsize from 125829120 to about 60000000
        Correct me if I am wrong.
      And the same for all the another database.
      

      * Now dbcachesize:
      

        ldapsearch -H ldaps://localhost -x
            -LLL -b "cn=monitor, cn=ldbm database, cn=plugins,cn=config"
            -D "cn=Directory Manager" -W "(objectclass=*)"  | grep
            dbcache
        Enter LDAP Password: 
        dbcachehits: 1440910461
        dbcachetries: 1440919648
        dbcachehitratio: 99
        dbcachepagein: 9187
        dbcachepageout: 128041
        dbcacheroevict: 9265
        dbcacherwevict: 0
      
      
      In some place I have read that
        dbcacheroevict and dbcachepageout should be 0 or increase the
        dbcachesize but if the ratio is 99 that should be ok, right?
      

      The thing is, if i search with db_stat
        for cache statistics says ratio=99
      

          db_stat -h /var/lib/dirsrv/slapd-xxx/db/
            -m
        0 Total cache size
        
          1
            Number of caches
        800MB Pool individual
            cache size
        0 Maximum memory-mapped
            file size
        0 Maximum open file
            descriptors
        0 Maximum sequential buffer
            writes
        0 Sleep after writing
            maximum sequential buffers
        0 Requested pages mapped
            into the process' address space
        1448M Requested pages
            found in the cache (99%)
        9588 Requested pages
            not found in the cache
        112 Pages created in the
            cache
        9588 Pages read into
            the cache
        129932 Pages written
            from the cache to the backing file
        9668 Clean pages
            forced from the cache
        1 Dirty pages forced from
            the cache
        0 Dirty pages written by
            trickle-sync thread
        98066 Current total
            page count
        98005 Current clean
            page count
        61 Current dirty page count
        131071 Number of hash
            buckets used for page location
        1447M Total number of
            times hash chains searched for a page (1447895423)
        5 The longest hash chain
            searched for a page
        2819M Total number of
            hash buckets examined for page location (2819107178)
        932 The number of hash bucket
            locks that required waiting (0%)
        86 The maximum number of
            times any hash bucket lock was waited for
        1 The number of region
            locks that required waiting (0%)
        9728 The number of
            page allocations
        60012 The number of
            hash buckets examined during allocations
        1381 The maximum
            number of hash buckets examined for an allocation
        9669 The number of
            pages examined during allocations
        1 The max number of pages
            examined for an allocation
        

      If I look for an index like
        inetuserstatus (pres and eq) I get "Requested pages found in the
        cache" less than 99% so I search for "inetuserstatus=*" (pres)
        and "inetuserstatus=active", "inetuserstatus=inactive" (eq) but
        the "requested pages" don't reaches the 99  or 100% and there is
        no more possibilities for that index.
      

      The thing is, why ns-sldapd is growing to
        consume all the swap and all the ram memory the SO lets it. 
      
        Any idea or suggestion???
      

        2012/11/15 Ludwig Krispenz <lkrispen@xxxxxxxxxx>

          
              you could use 

                ldapsearch ... -b  "cn=ldbm
                database,cn=plugins,cn=config" "cn=monitor"
                currententrycachesize

                
                to monitor the usage of the entrycache. 

                But be aware that the process uses more memory than just
                the caches and the memory manager can also generate some
                overhead.

                
                Regards,

                Ludwig
                
                  
                    On 11/15/2012 02:55 PM, Moisés Barba Pérez wrote:

                  
                  yes, thats correct, but
                    shouldn't use all that memory because don't need so
                    much memory
                    

                      2012/11/15 Ludwig
                        Krispenz <lkrispen@xxxxxxxxxx>

                        
                            Hi,
                              
                                
                                  On 11/15/2012 01:54 PM, Moisés Barba
                                  Pérez wrote:

                                
                                Hi,
                                  

                                  I have a memory issue with 389-ds
                                    1.2.5 in a CentOS 5.5 64bits 4GB
                                    ram. 
                                  

                                  The server swaps when the server
                                    physical memory increase over 75%
                                    approx. When the swap is full the
                                    server reaches 100% of physical
                                    memory and the SO kills the ns-ldapd
                                    process.
                                  

                                    Out of memory: Killed process
                                      30383, UID 99, (ns-slapd).
                                  
                                  
                                  The cache sizes are:
                                  

                                    nsslapd-dbcachesize: 838860800
                                    nsslapd-import-cachesize:
                                      20000000
                                    nsslapd-cachememsize: 125829120
                                      (for each 26 db)
                                  
                                
                            do you mean you have 26 db backends with
                            125MB entrycache each ? So you would reach
                            3.2GB for entrycache and 800MB dbcache.

                            
                            Regards,

                            Ludwig
                            

                                Which can be the problem?
                              
                              
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