1. Overview

1.1. Purpose of use

The Data Replication Xcelerator(DRX) is a DRBD proxy agent used for low-bandwith WAN replication.

DRBD asynchronous (A type) replication basically has better local I/O response performance than synchronous. However, since the size of the socket transmission buffer of the replication data transmission layer (TCP/IP) is limited, when the socket buffer becomes full at the transmission time, it is necessary to wait while the replication data is not transmitted and the I/O of the application program is not completed (This is the architecture of DRBD that asynchronously replicates the completion of data transmission as the completion of replication). In addition, since replicated data is transmitted remotely over a relatively low-bandwidth network, the latency of local I / O is further increased because there is less free buffer space for transmission, and a large amount of local I / O write requests Is encountered and exceeds the bounds of the socket send buffer, degradation of the local I / O response accompanied by replication is unavoidable. These I / O response degradation problems can be overcome using DRX's buffering mechanism.

In addition, DRX provides a replication acceleration (compression) function to increase the availability of remote data, and can greatly improve the target RPO (Recovery Point Objective). Also, by providing data encryption function, It also solves the security problems that may occur via the WAN network.

The following figure shows the DRX-DRBD buffering linkage.

• DRX buffering is performed from the local DRX prior to going through the WAN interval and does not require buffering on the remote DRX.

1.2. Considerations

DRX operates on DRBD-installed system or installed on dedicated server. A DRX instance can also act as a proxy for DRBD devices distributed across multiple nodes. Generally, DRBD activity log must be set in advance with sufficient capacity in case of large amount of data packet being transmitted at the time of transmission. If the primary node is corrupted while the excessive data packet is being processed at the sending time and the primary node is restarted, a large amount of activity log can be set to OOS and resynchronized for a long time. If you are concerned about this long synchronization, we recommend enabling DRBD's csums-alg setting.

1.3. Supported platforms

2. DRX Network

DRX can be configured in various ways as follows.

3. Installation

If the DRX is already installed on the operating machine, you only need to install additional DRX packages. However, if you separately configure DRX server, you need to install additional DRBD utility in addition to DRX package, and install QAT library when using HW compression.

This product supports both installation based on RPM and one based on GUI installer. The default installation location is the "/opt" directory.

3.1.1. Installation with Shell Script

The following is the screen output when installing with RPM:

3.1.4. DRX Watchdog on Linux

To manage DRX services, run a Linux DRX and a DRX monitor together. However, a DRX watchdog may restart DRX in the following cases:

• Termination of a DRX process on the unusual or unexpected situation: available to check the log in "/logs/service.log"
  
• Termination of DRX by the "drx-ctl -c shutdown" command on Linux: DRX restart occur by considering this case as unusual situation
  

Therefore, on Linux, you can use the following command to start or stop a DRX watchdog and DRX together:

3.2. Installation on Windows

An installer for installation on Windows is provided. You can install the product easily through this installer.

3.2.1. Automatic building DRX services on Windows

By using the installer, you can register DRX for the Windows service to restart the DRX service automatically whenever system is rebooted.

3.2.2. Manual building DRX services on Windows

Use the following commands to Install, start, shut down, or uninstall Windows services: 

• drxsvc /i: installing a service

• drxsvc /u: removing a service

• drxsvc /r: running a service on background

• drxsvc /k: stopping a service

3.2.3. DRX Watchdog on Windows

To manage DRX services, run a Linux DRX and a DRX watchdog together. Refer to the followings:.

• On Windows, its recovery policy is registered for the Windows service administrator occurs automatically when the first installation

• The recovery policy: it forces DRX to restart infinitely if it perceives unusual termination of the DRX process.

• Termination of DRX by the "drx-ctl -c shutdown" command on Windows: unlike on Linux, this case is considered as normal termination so the Windows service administrator would not run the recovery policy.

4. Uninstall

Log folder and configuration file and license file are not deleted. 

4.1. Windows

There are two ways to uninstall DRX as follows:

• Deleting DRX on the "Uninstall" program: on Windows, "Control Panel" > "Programs" > "Uninstall"
• Uninstalling by using the "uninstall.exe" command provided at the installation directory

4.2. Linux

• Uninstalling by using the "uninstall.exe" command provided at the installation directory

5. License File

License file is required for DRX operation.

• File name: "drx.lic"
• Directory path where the file should be installed: the directory where DRX has been installed(necessary authorization of users/groups: administrator or root)
  

For more information on licenses, contact to the Man Technology.

6. DRX Configuration

6.1. Configuration File

The DRX configuration is configured in the DRBD's configuration file. Set the buffer size in the "proxy" section and set the DRX ip address in the "proxy on" sub section of the host section.

DRX provides both a local method that is installed on the same system as DRBD and a dedicated machine configuration method that is installed and operated on a separate dedicated machine. By default, it is recommended that each node's configuration file use a "drbd.conf" configuration file with the same contents, so that each node has a consistent configuration. However, in some situations, it is not absolutely necessary to set the DRBD node and DRX configuration file resource names differently. To specify a different configuration file path or name, you can also specify the location of the configuration file using "-c" in the DRX executable option.

DRX works with DRBD by setting Proxy section and Proxy on section in the existing DRBD configuration file as follows. There are some differences in 1:1 replication configuration and 1:N replication configuration, as shown below.

6.1.1. Local method config

• In case DRX configuration on the same system as node1 and node2, the contents of "drbd.conf" on node1 and node2 are the same on both nodes.
• The following are examples of a 1:1 replication configuration and a 1:2 replication configuration
• Note that each port information must be covered by the firewall, and configured so that no ports are used redundantly.

resource r0 {
    device d minor 1;      
    disk d;                 
    meta-disk f;           

 	net {
        protocol A;
		on-congestion pull-ahead;
		congestion-fill 480M;
		ping-timeout 30;
    }

	proxy {
      	memlimit 500M; # DRX TX Buffer
  	}
 
	on node1 {
        address   10.10.0.250:7789;
        node-id 0;          
        proxy on node1 {
            inside 10.10.0.250:7790;
            outside 10.10.0.250:7791;
        }
    }
    
	on node2 {
        address   10.10.0.253:7789;
        node-id 1;
        proxy on node2 {
            inside 10.10.0.253:7790;
            outside 10.10.0.253:7791;
        }
    }
}

resource r0 {
    device /dev/drbd1;
    disk /dev/sdb1;
    meta-disk internal;
 	
	net {
		protocol A;
		on-congestion pull-ahead;
		congestion-fill 480M;
		ping-timeout 30;
	}
	proxy {
      	memlimit 500M; # DRX TX Buffer
  	}

    on node1 {
        address 100.100.10.31:7789;
        proxy on node1 {
            inside 100.100.10.31:7790;
            outside 100.100.10.31:7791;
        }
    }
    on node2 {
        address 100.100.10.41:7789;
        proxy on node2 {
            inside 100.100.100.41:7790;
            outside 100.100.100.41:7791;
        }
    } 
}

resource r2 {
  startup {
      wfc-timeout 1;
  }
  
	proxy {
      memlimit 500M;
  }
  
  net {
      protocol A;
      verify-alg crc32c;
      on-congestion pull-ahead; 
		sndbuf-size 20M;
      congestion-fill 480M;
      ping-timeout 30;
  }

  device e minor 2;
  disk	e;
  meta-disk	g "C:/r2_meta.vhd";

  on node1 {
    node-id	1;    
  }
  on node2 {
    node-id	2;
  }
  on node3 {
    node-id	3;
  }
  
  connection DR=node1=node3 { # Begin with DR and mark as delimiter between nodes =

	 host node1 address 100.100.100.9:6677 via proxy on node1 {
	 	inside 100.100.100.9:6678;
	 	outside 100.100.100.9:6679;
	 }
	 host node3 address 100.100.100.11:6677 via proxy on node3 {
	 	inside 100.100.100.11:6678;
	 	outside 100.100.100.11:6679;
	 }
  }

  connection DR=node2=node3 { # Begin with DR and mark as delimiter between nodes =

	 host node2 address 100.100.100.10:6680 via proxy on node2 {
	 	inside 100.100.100.10:6681;
	 	outside 100.100.100.10:6682;
	 }
	 host node3 address 100.100.100.11:6680 via proxy on node3 {
	 	inside 100.100.100.11:6681;
	 	outside 100.100.100.11:6682;
	 }
  }

  connection {
    host node1 address 10.20.25.9:6677;
    host node2 address 10.20.25.10:6677;
  }
}

global {
       disable-ip-verification;
               usage-count     no;
}
common {
       startup {
               wfc-timeout     1;
       }
}
resource r0{
       protocol A;
       disk {
               on-io-error detach;
       }
       net {
               ping-timeout 30;
       }
       syncer{
               rate 100M;
               verify-alg md5;
       }
       on pr1{
               device /dev/drbd0;
               disk /dev/sdb1;
               address 200.200.23.132:7799;
               meta-disk internal;
       }
       on pr2{
               device /dev/drbd0;
               disk /dev/sdb1;
               address 200.200.23.137:7799;
               meta-disk internal;
       }
}
resource r0_1{
       protocol A;
       meta-disk internal;
		device /dev/drbd10;
		proxy{
               memlimit 100M;
               plugin {
                       lzma level 9;
               }
       }
		net{
               on-congestion pull-ahead;
               congestion-fill 80M;
               ping-timeout 30;
       }
       stacked-on-top-of r0{
               address 127.0.0.1:7788;
               proxy on pr1 pr2{
                       inside 127.0.0.1:7789;
                       outside 10.30.0.135:7790;	# mirror VIP
               }
       }
       on dd1{
               address 127.0.0.1:7788;
               proxy on dd1 {
                       inside 127.0.0.1:7789;
                       outside 10.30.0.199:7790;     #DR mirror IP
               }
       }
}

6.1.2. Dedicated server configuration

By default, config file shoud be configured both nodes and DRX nodes identically. However, due to the nature of the dedicated server, DRX config needs to be modified to accommodate the characteristics of drbd-utils installed on the dedicated server to accommodate this type of node.

The procedure is as described below and the configuration examples are based on a Linux machine.

• Windows server
  • Copy the "drbdadm.exe" file to the DRX server
  • Create an etc folder in the parent folder of the folder where the "drbdadm.exe" file is located
  • Configure "drbd.conf" in the "etc" path

• Linux server
  • Install drbd-utils
  • Configure "drbd.conf" in the etc path

resource r0 {
	device    d  minor 1;
	disk      d;
	meta-disk e;

	proxy {
		memlimit 500M; # DRX TX Buffer
	}	
	disk {
		resync-rate 100M;
	}		
	net {
		protocol A;
		ping-timeout 30;
	}

	on w12std-0 {
		node-id 0;
	}
	on w12std-1 {
		node-id 1;
	}

	connection p-s {
		host w12std-0  address 10.10.0.77:7789 via proxy on 74proxy1 {
			inside 10.10.0.115:7790;
			outside 10.10.0.115:7791;
		}
		host w12std-1  address 10.10.0.203:7789 via proxy on 74proxy2 {
			inside 10.10.0.102:7790;
			outside 10.10.0.102:7791;
		}
	}

}

resource r0 {
        device /dev/drbd001; # dummy
        disk /dev/sdb1; # dummy
        meta-disk /dev/sdc1; # dummy

        disk {
                resync-rate 100M;
        }
        net{
                protocol A;
                ping-timeout 30;
        }
        proxy {
                memlimit 300M;  #drx tx buf
        }

        on w12std-0 {
                node-id 0;
        }
        on w12std-1 {
                node-id 1;
        }
        connection p-s {
                host w12std-0 address 10.10.0.77:7789 via proxy on 74proxy1 {
                        inside 10.10.0.115:7790;
                        outside 10.10.0.115:7791;
                }
                host w12std-1 address 10.10.0.203:7789 via proxy on 74proxy2 {
                        inside 10.10.0.102:7790;
                        outside 10.10.0.102:7791;
                }
        }
}

resource r1 {
	device /dev/drbd001;
	disk /dev/sdb1;
	meta-disk /dev/sdc1;

	disk {
		resync-rate 100M;
	}
	net{
		protocol A;
		ping-timeout 30;
	}
	proxy {
		memlimit 300M;  #drx tx bufl
	}

	on cen74-1 {
		node-id 0;
	}
	on cen74-2 {
		node-id 1;
	}

	connection DR-p-s {
		host cen74-1 address 10.10.0.11:7789 via proxy on 74proxy1 {
			inside 10.10.0.115:7790;
			outside 10.10.0.115:7791;
		}
		host cen74-2 address 10.10.0.105:7789 via proxy on 74proxy2 {
			inside 10.10.0.102:7790;
			outside 10.10.0.102:7791;
		}
	}
}

resource r0 {
        device /dev/drbd001; # dummy 
        disk /dev/sdb1; # dummy
        meta-disk /dev/sdc1; # dummy

        disk {
                resync-rate 100M;
        }
        net{
                protocol A;
                ping-timeout 30;
        }
        proxy {
                memlimit 300M;  #drx tx buf
        }

        on w12std-0 {
                node-id 0;
        }
        on w12std-1 {
                node-id 1;
        }
        connection p-s {
                host w12std-0 address 10.10.0.77:7789 via proxy on 74proxy1 {
                        inside 10.10.0.115:7790;
                        outside 10.10.0.115:7791;
                }
                host w12std-1 address 10.10.0.203:7789 via proxy on 74proxy2 {
                        inside 10.10.0.102:7790;
                        outside 10.10.0.102:7791;
                }
        }
}

resource r1 {
	device /dev/drbd001;
	disk /dev/sdb1;
	meta-disk /dev/sdc1;

	disk {
		resync-rate 100M;
	}
	net{
		protocol A;
		ping-timeout 30;
	}
	proxy {
		memlimit 300M;  #drx tx bufl
	}

	on cen74-1 {
		node-id 0;
	}
	on cen74-2 {
		node-id 1;
	}

	connection DR-p-s {
		host cen74-1 address 10.10.0.11:7789 via proxy on 74proxy1 {
			inside 10.10.0.115:7790;
			outside 10.10.0.115:7791;
		}
		host cen74-2 address 10.10.0.105:7789 via proxy on 74proxy2 {
			inside 10.10.0.102:7790;
			outside 10.10.0.102:7791;
		}
	}
}

resource r0 {
	device    d  minor 1;
	disk      d;
	meta-disk e;

	proxy {
		memlimit 500M; # DRX TX Buffer
	}	
	disk {
		resync-rate 100M;
	}		
	net {
		protocol A;
		ping-timeout 30;
	}

	on w12std-0 {
		node-id 0;
	}
	on w12std-1 {
		node-id 1;
	}

	connection p-s {
		host w12std-0  address 10.10.0.77:7789 via proxy on 74proxy1 {
			inside 10.10.0.115:7790;
			outside 10.10.0.115:7791;
		}
		host w12std-1  address 10.10.0.203:7789 via proxy on 74proxy2 {
			inside 10.10.0.102:7790;
			outside 10.10.0.102:7791;
		}
	}

}

resource r1 {
        device /dev/drbd0;
        disk /dev/sdb1;
        meta-disk /dev/sdc1;

        disk {
                resync-rate 100M;
        }
        net{
                protocol A;
                ping-timeout 30;
        }
        proxy {
                memlimit 300M;  #drx tx buf
        }

        on cen74-1 {
                node-id 0;
        }
        on cen74-2 {
                node-id 1;
        }

        connection DR-p-s {
                host cen74-1 address 10.10.0.11:7789 via proxy on 74proxy1 {
                        inside 10.10.0.115:7790;
                        outside 10.10.0.115:7791;
                }
                host cen74-2 address 10.10.0.105:7789 via proxy on 74proxy2 {
                        inside 10.10.0.102:7790;
                        outside 10.10.0.102:7791;
                }
        }

resource r1 {
	device /dev/drbd0;
	disk /dev/sdb1;
	meta-disk /dev/sdc1;

	disk {
		resync-rate 100M;
	}
	net{
		protocol A;
		ping-timeout 30;
	}
	proxy {
		memlimit 300M;  #drx tx bufl
	}

	on cen74-1 {
		node-id 0;
	}
	on cen74-2 {
		node-id 1;
	}

	connection DR-p-s {
		host cen74-1 address 10.10.0.11:7789 via proxy on 74proxy1 {
			inside 10.10.0.115:7790;
			outside 10.10.0.115:7791;
		}
		host cen74-2 address 10.10.0.105:7789 via proxy on 74proxy2 {
			inside 10.10.0.102:7790;
			outside 10.10.0.102:7791;
		}
	}
}

6.2. DRX configuration procedure

6.2.1. Local Method Configuration

6.2.2.  Dedicated Server Configuration

sc stop drxsvc

sc start drxsvc

If the above procedure is followed, DRBD and DRX will establish a connection and start replication.

6.3. Configuring DRX Properties

With a DRX property file, DRX can define its own properties, Apart from the DRBD configuration. Normally, you do not need to set up a property file because it works with DRX default settings.

This properties is applied when DRX is started. Here is a description of the corresponding DRX property file:

• file name: "drx.conf"
• path: The same directory as the executable file
• etc: You must specify "[global] section" at the beginning of this property file

properties

See the following table for the properties of the DRX property file.

drx.conf sample

7. Administrative command

Manage DRX with "drx-ctl" command.

7.1. Command

drx-ctl show 

Print information and status of currently configured resources.

C:\Users\sekim>drx-ctl show
Command : show
================================================================================================================================================================================
Name                             Type   Status         listen-lan-ip         remote-drx-ip          local-drx-wan-ip       local-drbd-ip               Up since
================================================================================================================================================================================
r0-2008r2-x64-pas1-2008r2-x64-act meta   established    10.10.0.245:7790         10.10.0.246:7791         10.10.0.245:7791         10.10.0.245:7789         2017-08-17 17:48:40
r0-2008r2-x64-pas1-2008r2-x64-act data   established    10.10.0.245:7790         10.10.0.246:7791         10.10.0.245:7791         10.10.0.245:7789         2017-08-21 09:18:58
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 All connections : 2

• Name: channel name
• type: data or meta
• Status: connection status
  • stopped: Stopped state
  • waiting: Waiting for connection
  • connecting: Connecting with local drbd
  • bridged: Local DRX and remote DRX connected
  • connected: Local DRX and Local DRBD Connected State
  • establishing: Local DRX and Remote DRX Connections, Local DRBD Connected State
  • established: Local DRX and remote DRX connection, local DRBD Remote DRBD both connected (replication established state)
• listen-lan-ip
• remote-drx-ip 
• local-drx-wan-ip
• local-drbd-ip
• up since: drbd/drx Start time.

drx-ctl show states

Print detail connection status of currently configured resources.

C:\Users\sekim>drx-ctl show states
Command id (4) : show states
=========================================================================================================================================================
Name                           Type local-drbd-ip         State          local-drx-ip                                State          remote-drx-ip
=========================================================================================================================================================
p-s-drxdev1-DESKTOP-L141PH6    data 192.168.35.112:7789   -established-> 192.168.35.1:7790/192.168.35.1:7791         <-bridged----- 192.168.35.101:7791
p-s-drxdev1-DESKTOP-L141PH6    meta 192.168.35.112:7789   <-established- 192.168.35.1:7790/192.168.35.1:7791         -----bridged-> 192.168.35.101:7791
---------------------------------------------------------------------------------------------------------------------------------------------------------
 All connections : 2, Established : 2

• Name: channel name
• Type: data or meta
• State: connection status (arrow: connection direction)
  • stopped: Stopped state
  • waiting: Waiting for connection
  • connecting: Connecting with local drbd
  • bridged: Local DRX and remote DRX connected
  • connected: Local DRX and Local DRBD Connected State
  • establishing: Local DRX and Remote DRX Connections, Local DRBD Connected State
  • established: Local DRX and remote DRX connection, local DRBD Remote DRBD both connected (replication established state)
• local-drbd-ip
• local-drx-ip
• remote-drx-ip

drx-ctl show memusage

Print the memory usage of the currently connected session.

C:\Users\sekim>drx-ctl show memusage
Command : show memusage
================================================================================================================================================
Name                             Capacity                   Begin            End              Size                       Full Counts      Use
================================================================================================================================================
r0-2008r2-x64-pas1-2008r2-x64-act 1073741824 (1.00 GB)       829              829              0 (0.00 B)                 0                0 %
                                  10485760 (10.00MB)         0                0                0 (0.00 B)                 -                0 %
------------------------------------------------------------------------------------------------------------------------------------------------
 Active bab counts : 1
-------------------------------------------------------------------------------------------------------------
name                              Latency              cur              avg              max              min
=============================================================================================================
r0-2008r2-x64-pas1-2008r2-x64-act  TX BAB  00:00:00.105064  00:00:00.104454  00:00:00.105833  00:00:00.102081
                                   RX BAB  00:00:00.000000  00:00:00.000000  00:00:00.000000  00:00:00.000000
                                 Compress  00:00:00.000038  00:00:00.000068  00:00:00.000120  00:00:00.000038
                               Decompress  00:00:00.000019  00:00:00.000037  00:00:00.000063  00:00:00.000019
-------------------------------------------------------------------------------------------------------------

• Name: channel name
• Capacity: The amount of memory used for buffering
• Begin: Memory start offset of the ring buffer currently in operation
• End: Offset of last memory point in ring buffer currently in operation
• Size: The amount of memory currently being used for buffering
• Full Counts: Buffer congestion state hit count
• Use: Percentage of current usage relative to total buffered memory(%)
• Latency: BAB/compress/uncompress latency statistics

drx-ctl show connections

Shows the status of the currently connected DRBD resource unit.

C:\Users\sekim>drx-ctl show connections
Command : show connections
======================================================================================================================================================================================
Name                             Type     TX.raw         TX.net         TX.Ratio       Tx.Speed       RX.raw         RX.net         RX.Ratio       RX.Speed       Up since
======================================================================================================================================================================================
r0-2008r2-x64-pas1-2008r2-x64-act meta     18.54 GB       36.23 MB       52,416 %       27.00 B        51.36 KB       85.71 KB       59 %           27.00 B        2017-08-17 17:48:40
r0-2008r2-x64-pas1-2008r2-x64-act data     305.84 KB      412.21 KB      74 %           0.00 B         1.75 MB        2.55 MB        68 %           0.00 B         2017-08-21 09:18:58
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Active connections : 2

• Name: channel name
• TX.raw: Amount of packets to send remotely
• TX.net:The amount of packets transmitted remotely (separated from TX.raw in compression / encryption)
• TX.ratio: TX compression ratio
• TX.speed: TX speed
• RX.raw: Amount of packets to send locally
• RX.net: The amount of packets transmitted locally (separated from RX.raw in compression / encryption)
• RX.ratio: RX decompression ratio
• RX.speed: RX speed
• Up since: connection established time

drx-ctl print statistics 

Details of the currently connected session are output in an analytical format.

C:\Users\sekim>drx-ctl print statistics
Command : print statistics
================================================================================
 Name : r0-2008r2-x64-pas1-2008r2-x64-act
================================================================================
   * options
      memlimit: 1.00 GB
      bwlimit: 0.00 B
      bab-read-spin-counter: 10
      block-size: 64512 (63.00 KB)
      bab-read-spin-delay: 10
      min-raw-block-size: 0
      compressor: ZLIB level: 9
      crypto: OPENSSL
      crypto-key-file:
   * available plugins
      ZLIB
      LZMA
      OPENSSL
   ----------------------------------------
   * session
      drbd stream type: data
      connected: 2017-08-17 17:48:40
      up time: 1 mins 40 secs
      status: established
      * tx
       raw packets: 6.28 GB
       net packets: 12.24 MB
       speed: 0.00 B
       * compress ratio
          average: 1.79152
          best: 20.3922
          worst: 1.05263
       * compress time
          counts: 104555
          average: 00:00:00
          max: 00:00:00.015601
          min: 00:00:00
       * encrypt time
          counts: 104555
          average: 00:00:00
          max: 00:00:00.015601
          min: 00:00:00
      * rx
       raw packets: 725.00 B
       net packets: 262.00 B
       speed: 0.00 B
       * decompress time
          counts: 2
          average: 00:00:00
          max: 00:00:00
          min: 00:00:00
       * decrypt time
          counts: 2
          average: 00:00:00
          max: 00:00:00
          min: 00:00:00
   ----------------------------------------

drx-ctl set bwlimit <channel name> <bwlimit-in-bytes>

DRX supports resource-specific bandwidth limiting during operation. You can limit the network bandwidth that DRX operate, and then it transmits data within the specified bandwidth. The default value is 0, which means that the bandwidth is unlimited.

<channel name> must specify the connection channel name used internally by DRX. This channel name can be extract through the drx-ctl show command.

C:\Users\sekim>drx-ctl show
Command : show
==============================================================================================================================================================================================
Name                             Type   Status         listen-lan-ip         remote-drx-ip          local-drx-wan-ip       local-drbd-ip               Up since
==============================================================================================================================================================================================
active-standby-2008r2-x64-pas1-2008r2-x64-act data   established    10.10.0.245:7790         10.10.0.246:7791         10.10.0.245:7791         10.10.0.245:7789         2018-02-07 13:08:51
active-standby-2008r2-x64-pas1-2008r2-x64-act meta   established    10.10.0.245:7790         10.10.0.246:7791         10.10.0.245:7791         10.10.0.245:7789         2018-02-07 13:08:50
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
All connections : 2

C:\Users\sekim>drx-ctl set bwlimit active-standby-2008r2-x64-pas1-2008r2-x64-act 10MB
Command : set bwlimit active-standby-2008r2-x64-pas1-2008r2-x64-act 10MB
Result: done.

proxy {
     bwlimit 2M;
}

The above example limits the bandwidth to about 2MiB/s by setting drbd.conf without using the set bwlimit command.

drx-ctl shutdown 

shutdown DRX. However, it is automatically restarted by the DRX Watchdog, so it is also used as a function to restart DRX.

8. Log

8.1. Saving method and log level

The DRX logs provide the following saving methods:

• file
  
• system log
  
  • Linux: service.log

The log levels for the DRX log are:

• debug < info < warn < err < fatal < none
• none means no logging.

8.2. Log setting

The log setting can be applied at the start of DRX by specifying the corresponding property in the "drx.conf" file or by using "drx-ctl" command. Use the log level to determine the saving method and level.

Here is how to set "drx-ctl" for this operation.

• drx-ctl -c set loglevel-file <level>

9. Command options

For a detailed command options, see:

drx 

• Example
  • Option "-c"

    C:\Users\dgkim\Downloads>drx -f -c c:\drx.conf
     loading config : [c:\drx.conf]
    ...skip...

drx-ctl 

drxsvc

10. Etc

• oom-kill due to memory usage.
  
  • oom-kill is caused by excessive use of memory on the operation server. so oom_adjust of DRX parameter have been changed.