bionic (8) atopacctd.8.gz

Provided by: atop_2.3.0-1_amd64 bug

NAME

       atopacctd - process accounting daemon

SYNOPSIS

       atopacctd [-v | topdirectory]

DESCRIPTION

       The  atopacctd  daemon  switches  on  the  process  accounting  feature in the kernel and let the process
       accounting records be written to a file, called the source file from now.  After  process  accounting  is
       activated, the atopacctd daemon transfers every process accounting record that is available in the source
       file to a shadow file.  Client processes (like atop processes) will read the shadow files instead of  the
       process accounting source file.
       In  this  way,  the  atopacctd  daemon  operates as a 'layer' between the process accounting file that is
       written by the kernel and the shadow accounting files that are read by atop processes.

       This approach has the following advantages:

       o  The atopacctd daemon takes care that the source file is kept to  a  limited  size.   As  soon  as  its
          maximum  size  is  reached,  it  is truncated to a size of zero again (this is not noticed by the atop
          processes).

       o  The atopacct daemon takes care that a shadow file is kept to a limited size.  As soon as  the  current
          shadow  file  reaches  this maximum size, the atopacctd daemon creates a new (subsequent) shadow file.
          While client processes still have the possibility to read the previous shadow file(s),  the  atopacctd
          daemon continues writing accounting records to the newest (current) shadow file.  For this reason, the
          name of a shadow file consists of a 10-digit sequence number followed by the extension '.paf' (process
          acounting  file).   Old shadow files that are not used by client processes any more, are automatically
          removed by the garbage collector in the atopacctd daemon.

       o  When no client processes are active (any more), all shadow files will be deleted and no  records  will
          be  transferred  to  a  shadow  file  any  more. As soon as at least one client is activate again, the
          atopacctd daemon continues writing shadow files.

       The directory /run is used as the default  topdirectory.   Below  this  top-directory,  the  source  file
       pacct_source is created to which the kernel writes the process accounting records.
       Furthermore,  the  subdirectory  pacct_shadow.d  is created as a 'container' for the shadow files.  Apart
       from the shadow files, also the file current is maintained in this subdirectory, containing the  sequence
       number of the current (newest) shadow file and the maximum number of records that will be written in each
       shadow file.

       An alternative topdirectory can be specified as command line argument.  When an alternative  topdirectory
       is  defined, also modify the configuration file /etc/atoprc to inform atop clients about this alternative
       location (see the atoprc man page).  Such alternative topdirectory should be owned by root and may not be
       writable for the group or others (security reasons).

       Notice  that the kernel suspends writing process accounting records when the free space of the filesystem
       on which the process accounting file resides drops below 2%. Writing is resumed when the free space is 4%
       or  more.   These  lowwater  and  highwater  percentages  can be configured via the /proc/sys/kernel/acct
       pseudo-file.
       The atopacctd daemon suspends transferring process accounting records to shadow files when the free space
       of  the  filesystem on which the process accounting file resides drops below 5%. Transfer is resumed when
       the free space is 5% or more.  Log messages are generated via syslog when writing to the  current  shadow
       file is suspended or resumed.

       The -v flag can be used to verify the version of the atopacctd daemon.

FILES

       /run/pacct_source
            Regular file to which the kernel writes the process accounting records.  This file will be regularly
            truncated.

       /run/pacct_shadow.d/current
            Regular file containing the sequence number of the current shadow file and  the  maximum  number  of
            records per shadow file.

       /run/pacct_shadow.d/N.paf
            Regular files containing the process accounting records that have been copied transparently from the
            source file (N represents a 10-digit sequence number).

SEE ALSO

       atop(1), atopsar(1), atoprc(5), netatop(4), netatopd(8)
       http://www.atoptool.nl

AUTHOR

       Gerlof Langeveld (gerlof.langeveld@atoptool.nl)