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How to use EMS(Emergency Message Service)

MCCS has a bundled product called EMS(Emergency Message service) that automatically sends SMS to the defined admin members in charge of critical events. 
In addition, since console is web-based management, whenever an error or fault occurs, it can be managed anywhere that has internet service. Plus, Failures records in the past, management, reporting are all very easy to use.

EMS Component

EMS Agent

It is a program installed in the server to connect with EMS server.

EMS Server

It is an installed server program from the product provider company of MCCS.

EMS Workflow

Save Log

EMS Agent saves logs.
EMS server can specify logs by its type using 'LogType' attribute as shown below.

H

It saves the logs related to HA (MCCS).
(It can only specify file monitor.)

A

It saves logs related to application.
(It can only specify file monitor.)

S

It saves event log of Windows system.
(It can only specify Windows event monitor.)

P

It saves log related to process.
(It can only monitor specified file.)

Log Analysis

EMS Server users can set failure level of the system that wants to receive EMS service.
EMS server uses failure level that is set to filter EMS Agent system of operating server and analysis log to determine if it is a failure

SMS Notification

After failure monitoring for given filter is checked, EMS will send the SMS to the system operator and MCCS server operator so that it can be dealt quickly.

After connecting to EMS server, analysis cause of failure

System operator and MCCS service operator can access to the EMS server where anywhere with internet connection to check on the log and analyze the cause.
In addition, in case of manufacturing customer, it provides a centered monitoring system for all the servers in the factory and also provides a statistic of periodical failure type and trouble-shooting solutions.
The following graph is the workflow if EMS system.

Image Removed

[Figure] Workflow of EMS System

Control Monitoring of EMS Server Consolidated Web-based dashboard of EMS Server

Following is a part of consolidated web-based dashboard of EMS Server. 
Servers with failures are shown in red, servers that had failure and had notified to the server operators are shown in yellow, and servers that operate normally are shown in blue.
Users registered in EMS server are the only ones that can monitor the dashboard. 

Image Removed

[Figure] Redundant server monitoring view of EMS system

Image Removed

[Figure] Statistic view of EMS system 

Server Failure

This is the case of system being rebooting or shut down because of conflicts of each device (NIC, Raid Controller), kernel driver problem of other application.

Active Server Failure

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• • Normal Termination of a system
    This is a case where user selected 'system shutdown' in operating systems.
  • Abnormal Termination of a system 
    This is a case where system is terminated or rebooted due to an unexpected situation or blue screen.

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Standby Server Failure

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Application Failure

Active application resources are operated by 4 elements below.

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Network Failure

Network failure happens when network connection has problem, such as network switch or network interface card is broken or disconnection in network cable, or ping timeout of some network and so on.

• Service Network Failure

  If failure occurs in service network of active server, the fault mark will be shown on the network interface card resource or IP address of the node in MCCS UI, and will failover to the standby server.

  Image Removed

  [Figure] Failure in Network Interface Card

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Heartbeat Network Fault

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Server Failure

This is the case of system being rebooting or shut down because of conflicts of each device (NIC, Raid Controller), kernel driver problem of other application.

Active Server Failure

1. There is no difference in the MCCS role resulting from abnormal or normal termination of the server.
   MCCS will perform a failover to the standby server when the operation server fails. In the node management menu on the right side of the screen, select the server.
   You can check the details of failures in the 'Resource Status' & 'Resource Dependency' screens.
   • • Normal Termination of a system
       This is a case where user selected 'system shutdown' in operating systems.
     • Abnormal Termination of a system 
       This is a case where system is terminated or rebooted due to an unexpected situation or blue screen.
   Image Added
   [Figure] Failure in Active Server
   
   
2. Since data cannot be replicated due to the server failure, Image Addedwill be shown in the mirror disk resource.
3. Server operators check on the failure and put the server back to normal.
4. After checking on the mirror role of two servers when server with the failure is rebooted, switch the server with the failure as replication target and proceed partial resync.

Standby Server Failure

1. MCCS will show the failure when failure occurs in standby server.
2. Data replication will be paused until standby server is back to normal.
   
   Image Added
   [Figure] Failure in Standby Server
   
   
3. Data synchronization cannot be achieved. Mirror disk becomes the 'Network Connection Failure' state ( Image Added ).
4. Even if the standby server failed, it does not affect operation. But as there is no server to perform failover to, the server operator must check the trouble in the MCCS web console and make sure that the standby server is normalized in time.
5. When the standby server is normalized, the Image Added icon disappears.
6. Mirror disk's DiskState value is changed from 'Inconsistent' to 'UpToDate' and for this purpose, data synchronization (Image Added) is performed. 
7. When the synchronization is finished, the current normal data is synchronized in real time. The icon is changed to Image Added. 

Application Failure

Active application resources are operated by 4 elements below.

• MonitorInterval (Default Value=10sec)
  Monitors the resource with interval set value.
• MonitorTimeout (Default Value=10sec)
  If there is no reply as much as the set value, it is considered as a failure.
• RestartLimit (Default Value=0)
  It will restart the application resource as the set value.
• OnlieTrustTime (Default Value=600sec) 
  It re-sets the time of number of resource restarting number.It is the time to reset the frequency of the resource to restart.
  Attributes above are the set value of the registered being added the resource, and users can check or change the values through Resource Attribute view of MCCS console. 
  
  Image Added
  [Figure] Resource attribute value Edit
  
  

1. MCCS periodically monitors the resources referring  'MonitorInterval'.
2. If there is no response as the time set in 'MonitorTimeout', it is considered as a failure.
3. If there are no response after sending the command as the number set in 'RestartLimit', MCCS will failover the group which resource belongs to.
4. If the resource stays in normal state within the time limit set by 'OnlineTrustTime'. MCCS will initialize the attribute value of 'RestartLimit'. This is to ensure restart number when failure occurs in a resource.
5. If there is a failover due to a failure in the resource, server operator checks on the problem and put it back to normal.
6. In the MCCS web console, a user can see where the trouble occurs. After a user checks the trouble area, they must remove the Trouble sign, so that the failover function can be activated again. 
   If you want the sign of failures to be removed automatically, enter a positive number in AutoFaultClearTime of the group attribute. 
7. After checking on the mirror role of two servers when server with the failure is rebooted, switch the server with the failure as replication target and proceed partial resync.
   
   Image Added
   [Figure] Failure in Resource Clear
   

Network Failure

Network failure happens when network connection has problem, such as network switch or network interface card is broken or disconnection in network cable, or ping timeout of some network and so on.

• Service Network Failure

  If failure occurs in service network of active server, the fault mark will be shown on the network interface card resource or IP address of the node in MCCS UI, and will failover to the standby server.

  Image Added

  [Figure] Failure in Network Interface Card

1. In the MCCS web console, you can check in which part of service network, trouble has occurred.
2. MCCS checks network cable disconnection of server where network failure occurred, and whether ping timeout occurs from network.
3. If IP address resource is the cause of the failure, user should check on the network switch or network interface card.
   When physical parts related to network is back to normal, select 'Clear Fault' from the MCCS web console and remove fault mark in order to re-enable the failover function. 
4. If you want the sign of failures to be removed automatically, enter a positive number in AutoFaultClearTime of the group attribute. 
   
   

• • Heartbeat Network Fault

    Heartbeat should be dualized because it plays a very important role of synchronizing the inter node status and determining the condition of failure. If any one of the dualized heartbeat network fails, the details of failure is displayed in the log window.
    However, the MCCS web console has no changes. It means that the operation server or the standby server has no problems. 
    At this point, when failure occurs in active server and needs to failover to the standby server, MCCS will use redundant normal heartbeat network to failover.
    If all the redundant heartbeat is disconnected, MCCS will use the service network as heartbeat line.

    Image RemovedImage Added

    [Figure] Failure in Heartbeat
    
    

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• • Replication (Mirroring) Network Failure

    복제 네트워크에 장애가 발생하면 데이터 복제를 진행할 수 없으며, MCCS 웹 콘솔의 미러 디스크 리소스 부분이 'Disconnect' 상태( Image Removed )로 표시 됩니다.

    Image RemovedWhen the copying network failed, data copying cannot be done. The mirror disk resource of MCCS web console displays the 'Disconnect' ( Image Added).

    Image Added

    [Figure]Failure in Replicated Network

    
    

1. Replication network failure can be checked on MCCS log, OS System log. If failure occurs in replication network, server operator should check on the TCP/IP of server, physical connection check on the replication network through ping test.
2. If it is an abnormal situation, check on card, cable connection or cable disconnection and clear the cause of the failure.
   
   
   

• • Single Network Switch Fault

    When failure occurs in network switch connected to Public Network where it is configured by single network switch, all the resources in active and standby server will be taken offline, resources where failure occurs will show as 'fault'.
    Image RemovedImage Added
    [Figure] Failure in Network Switch    

1. Network switch failure can be checked on MCCS log, OS System log. If failure occurs in service network connection, server operator should check on the TCP/IP of server, physical connection check on the service network through ping test.자동으로 장애 표시를 제거하려면 그룹 속성의 AutoFaultClearTime에 0보다 큰 값을 설정하면 됩니다/IP of server, physical connection check on the service network through ping test.
2. If you want the sign of failures to be removed automatically, enter a positive number in AutoFaultClearTime of the group attribute.
3. Please get the supports regarding the recovery of Network switch failure through manufacturer.
   
   
   
   

Disk Failure

Mirror Disk Failure

• Source Disk Failure

  If failure occurs in disk resource of active server, MCCS GUI will show the failure. MCCS will failover to the standby server since it is impossible to Read/Write in the disk.

  Image RemovedImage Added 

  [Figure] Failure in Mirror Disk

  
  

1. Availability of disk monitoring of MCCS are as below.
   
   • Periodic read/write test on the disk.Determines whether drive letter exists in the disk.
     
   디스크 장애 발생 요인은 다음과 같은 경우가 있을 수 있습니다. 위의 문제가 해결 된 후에 운영 체제는 변경된 디스크를 다시 인식합니다.이후 DRBD에서 동기화를 진행합니다.
2. 디스크 컨트롤러 문제 하드웨어 자체의 문제는 해당 업체에서 해결해야 합니다.
물리적인 디스크 문제 하드웨어 자체의 문제는 해당 업체에서 해결해야 합니다.
미러 리소스에서 동기화가 진행되지 않으면 미러디스크 리소스를 삭제한 후에 다시 생성해야 합니다. 단, 삭제 시 리소스만 삭제가 아니라 생성된 미러까지 삭제하고 다시 생성해야 합니다. 

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1. MCCS에서 타깃 디스크에 대한 장애 감지는 해당 디스크의 DiskState 상태에 대한 값만을 출력합니다. 
2. 디스크 장애 발생 요인은 다음과 같은 경우가 있을 수 있습니다.위의 문제가 해결 된 후에 운영 체제는 변경된 디스크를 다시 인식합니다.이후 DRBD에서 동기화를 진행합니다.
   • 디스크 컨트롤러 문제 하드웨어 자체 문제는 해당 업체에서 해결해야 합니다.
   • 물리적인 디스크 문제 하드웨어 자체 문제는 해당 업체에서 해결해야 합니다.
3. 미러 리소스에서 동기화가 진행되지 않으면 미러디스크 리소스를 삭제한 후에 다시 생성 해야합니다. 단, 삭제 시 리소스만 삭제가 아니라 생성된 미러까지 삭제하고 다시 생성해야 합니다
   • test on the disk.
   • Determines whether drive letter exists in the disk.
     
     
4. Disk failure can be caused by the following. After resolving the above issues, the OS will detect the newly changed disk again. After that, DRBD will proceed with synchronization.
   
   • Disk controller problems or H/W problems should be fixed by the manufacturers.
   • Physical disk problems or H/W problems should be fixed by the manufacturers.
     
     
5. If the mirror disk does not perform synchronization, delete the mirror disk resource and try to create it again. But when you delete the resource, you must also delete the created mirror and create them again. 
   
   

• Target Disk Failure
  If the disk at the standby server failed, the disk resource icon of MCCS web console is not changed. But the attribute values of Diskstate is changed from UptoDate to Diskless. However, the service running in the source server is not affected by it. 
  Image Added
  [Figure] Failure in Target Disk
  
  

1. When MCCS detects failures of the target disk, only the DiskState value of the disk is displayed. 
2. Disk failure can be caused by the following. After resolving the above issues, the OS will detect the newly changed disk again. After that, DRBD will proceed with synchronization.
   • Disk controller problems or H/W problems should be fixed by the manufacturers.
   • Physical disk problems or H/W problems should be fixed by the manufacturers.
3. If the mirror disk does not perform synchronization, delete the mirror disk resource and try to create it again. But when you delete the resource, you must also delete the created mirror and create them again. 
   
   

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•  MCCS 웹 콘솔을 사용해서 스플릿브레인을 해결하는 방법

리소스 속성창을 확인합니다. 
Image Removed
[그림] 미러디스크 스플릿 브레인 확인

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미러 관리창을 확인합니다.

Image Removed
[그림] 미러디스크 스플릿 브레인 확인

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External Storage Failure

외장 디스크의 연결 경로 및 디스크에 장애가 발생하면 해당 디스크의 Read/Write가 불가능하므로 MCCS는 장애를 표시하고 페일오버를 진행합니다.

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• Split Brain of Mirror Disk Resource 

  매우 드문 경우이지만 두 서버상에서 미러 디스크 역할이 모두 Primary로 인식되었고, 웹 콘솔의 데이터 값이 불일치 하는 경우입니다. 
  이러한 상황은 타깃이 소스로 변경되는 시점에 기존 소스가 타깃으로 변경되지 못한 결과이며, 이 때는 서로 자신의 데이터를 동기화하려 하지만 이전 데이터 값이 불일치하기 때문에 자동으로 동기화하지 않게 됩니다. 
  미러 디스크에서 Split Brain이 발생하는 상황은 다음과 같습니다.
  

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• This is a rare case but in this case, the mirror disk roles at the two servers are recognized as primary and the data on the web console is not matched.
  The situation arises because the existing source is not switched to the target when the source and the target need to be switched. In this case, they try to synchronize their own data but due to the mismatch between the previous data, automatic synchronization failed. 
  In the mirror disk, a split brain can occur as follows.

1. Due to the failure of source server (A), a failover occurs.
2. The role of target server (B) is changed to Primary. (Mirror disk role changed)
3. Reboot the initial source server (A).
4. After the initial source server (A) boots, check the role of the target server (B).
5. Check the GI value for the both nodes.
6.  Check if the GI data is matched, and if it is, proceed with data synchronization automatically. (5th/ 6th processes checking fails.)
7. GI data is not matched. So, synchronization is required on one node. No automatic synchronization is taking place.  (Split brain occurred.)
    
   When this state is reached, the icon of mirror disk resource is overlapped in the MCCS web console. Both the Image Added and the 'SplitBrainStatus' attribute values will be set to true.
   In this case, you need to manually change the mirror disk role. After that, you need to resynchronize it.
   If you want to manually change the mirror disk role, you need to use the MCCS web console. 
   
   

•  How to resolve the split brain issues by using the MCCS web console

1. Check the resource attribute view. 
   Image Added
   [Figure] Verify SplitBrain of MirrorDisk

   
   

2. Check the mirror management view.

   Image Added
   [Figure] Checking Mirror Disk Split Brains
   
   

   Warning

   1) The ConnectState of both node is StandAlone and SplitBrainStatus values are set to True. 2) Check LastMirrorOnlineTime on the mirror disk. (LastMirrorOnlineTime is the system time. So, it is not the absolute value used to determine whether it is the latest data.) 3) When a split brain occurs, the log will be displayed. (DRBD volume (r0) has a split brain.) 4) In the mirror management window, the mirror condition is set to 'SPLIT'.

3. Select the mirror disk and right click with your mouse button and click on 'Resolve Split Brains'.
   Image Added
   [Figure] Split Brain Resolving Selected
   
   
4. Display the window to explain split brains.
   Image Added 
   [Figure] Checking the Source Node Selection
   
   
5. Select the source node.
   Image Added
   [Figure] Source Roll Node Selection
   
   
6. Recheck the selected source node.
   Image Added
   [Figure] Rechecking the Source Node Selection
   
   
7. Split brains problems being resolved.
   Image Added
   [Figure] Split Brain Resolved
   
   
8. Resolving split brains problems is finished.
   Image Added
   [Figure] Resolving Split Brain Finished
   
   

9. The selected node becomes the source node and the mirror disk condition is changed from DiskState to UpToData. 
   Image Added
   [Figure] Split Brain Resolve
   
   

   Warning
   The changed information of node B will be all overwritten.

External Storage Failure

When the external disk fails or has a bad connection path, you cannot read/write the disk. So, MCCS will display the sign of failure and proceed with a failover.

Image Added

[Figure] Failure in Shared Disk

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When interlock with volume manager using SCSI3-PR

Volume Manager (Ex: something like SFW of Symantec that has SCSI3-PR reservation function) can be used with SCSI Lock agent.

When check if SCSI-PR is supported

To check of the disk supports SCSI-3PR function, PR type can be checked using scsicmd.cmd command.

When interlock with shared disk

When interlock shared disk agent and SCSI Lock agent, check if the shared disk agent works normally and then register SCSI Lock agent.
The purpose of disk of SCSI Lock agent is to use as a LOCK device in hardware perspective, not the contents of the disk. Therefore, size of disk can be small and it is not protected.

When registration key error occurs

Remove Reservation key and registration key using scsicmd.cmd-c command and re-set. Before registering resource, check if there is any registered key and if there is any registered key and if there is, remove the key first before registering.
Note that the current key is se automatically by its MAC address. It uses the first adapter among the network adapters. This key is automatically recorded in setting file. If key does not exist in setting file then new key is not created.

When various letters exist in one disk and when register one letter, other letters cannot access

SCSI Lock disk supports basic disk and single letter. Please do not use the disk that uses dynamic disk or multiple volume(use one LUN to configure various partition).

When maintaining the state where DUID is not solved after registering agent

레터를 정의하고 활성화를 요청해야 main.json에 해당 레터에 연결된 DUID 정보가 기록됩니다.

When delete agent

SCSI Lock 에이전트가 삭제될때 예약을 해제합니다. 따라서 예약대상 공유디스크가 상대 노드에서 사용될 가능성을 염두에 두고 삭제를 해야 합니다. 즉 삭제할 경우에는 상대 노드를 다운시킨 후 작업하십시요.is, remove the key first before registering.
Note that the current key is se automatically by its MAC address. It uses the first adapter among the network adapters. This key is automatically recorded in setting file. If key does not exist in setting file then new key is not created.

When various letters exist in one disk and when register one letter, other letters cannot access

SCSI Lock disk support single disk device. Please do not use the disk that uses multiple volume(use one LUN to configure various partition).

When maintaining the state where DUID is not solved after registering agent

You must first define the disk device and request activation before the information of DUID connected to the letter is recorded in main.json.

When delete agent

Reservation is canceled when an SCSI Lock agent is deleted. When you delete it, you must consider the fact that the shared disk to be reserved can be used at the other node. In other words, when you delete it, you must make sure the other node is down.

Ways to collect support files

When problems occur in MCCS, support file must be collected to collect log and preference information.
There are 2 ways 2 ways to collect support file.

How to collect by using the web console

1.  In the MCCS web console, click 'File' on the menu bar to collect support

...

1. files.
   

웹 콘솔로 수집하는 방법

1. MCCS 웹 콘솔에서 메뉴바의 '파일'을 클릭하여 서포트 파일을 수집할 수 있습니다.
   Image RemovedImage Added
   [그림] 메뉴바에서 서포트 파일 수집 Figure] Collecting Support Files from Menu Bar  
   
   
2. Support files can be collected by clicking the toolbar shown in the figure below.
   Image RemovedImage Added
   [그림] 툴바에서 서포트 파일 수집
   서포트 파일을 수집할 노드의 선택과 이전에 받은 서포트파일을 다시 받을 수 있습니다.
   Image Removed
   [그림] 서포트 파일 노드 선택 및 이전 서포트 파일 선택 여부Figure] Collecting Support Files from Toolbar
   
   
3. You can select a node to collect support files from and get the previous support file again.
   Image Added
   [Figure] Support File Node Selection and Previous Support File Selection
   
   

4. Click 'OK' button and support file is collected.
   Image RemovedImage Added
   [그림] 서포트 파일 수집 중 화면

    

   Info
   로그파일의 용량과 네트워크의 상태에 따라서 몇 분이 걸릴 수도 있습니다.

   아래와 같이 다운로드 창이 열리게 되고 다운받으시면 됩니다.
   Image Removed
   수집된 서포트 파일은 지정된 위치에서 확인할 수 있습니다.
   Image Removed
   [그림] 서포트 파일

   Figure] Support Files Being Collected

    

   Info
   It may take several minutes depending on the log file capacity and the network condition.

5. The collected support files can be checked in the designated location.
   Image Added
   [Figure] Support Files

Collecting file using script files

Script file is located as below:

$MCCS_HOME/bin/Support/support.cmd

Collected support file is created in the following directory.

$MCCS_HOME/support-$HOSTNAME/$HOSTNAME.zip