Storage Foundation for Sybase ASE CE 7.4 Administrator's Guide - Linux

Last Published:
Product(s): InfoScale & Storage Foundation (7.4)
Platform: Linux
  1. Overview of Storage Foundation for Sybase ASE CE
    1. About Storage Foundation for Sybase ASE CE
      1.  
        Benefits of SF Sybase CE
    2.  
      How SF Sybase CE works (high-level perspective)
    3. About SF Sybase CE components
      1. Communication infrastructure
        1.  
          Data flow
        2.  
          Communication requirements
      2. Cluster interconnect communication channel
        1.  
          Low Latency Transport
        2.  
          Group Membership Services/Atomic Broadcast
      3.  
        Low-level communication: port relationship between GAB and processes
      4. Cluster Volume Manager (CVM)
        1.  
          CVM architecture
        2.  
          CVM communication
        3.  
          CVM recovery
        4.  
          Configuration differences with VxVM
      5. Cluster File System (CFS)
        1.  
          CFS architecture
        2.  
          CFS communication
        3.  
          CFS file system benefits
        4.  
          CFS configuration differences
        5.  
          CFS recovery
        6.  
          Comparing raw volumes and CFS for data files
      6. Cluster Server (VCS)
        1.  
          VCS architecture
        2. VCS communication
          1.  
            About the IMF notification module
        3. About resource monitoring
          1.  
            How intelligent resource monitoring works
        4.  
          Cluster configuration files
      7. About I/O fencing in SF Sybase CE environment
        1.  
          About preferred fencing
        2. About preventing data corruption with I/O fencing
          1.  
            About SCSI-3 Persistent Reservations
          2.  
            About I/O fencing operations
          3. About I/O fencing components
            1.  
              About data disks
            2.  
              About coordination points
          4.  
            How I/O fencing works in different event scenarios
      8.  
        Sybase ASE CE components
    4. About optional features in SF Sybase CE
      1.  
        Typical configuration of SF Sybase CE clusters in secure mode
      2.  
        Typical configuration of VOM-managed SF Sybase CE clusters
      3.  
        About SF Sybase CE global cluster setup for disaster recovery
    5.  
      How the agent makes Sybase highly available
    6.  
      About Veritas InfoScale Operations Manager
  2. Administering SF Sybase CE and its components
    1. Administering SF Sybase CE
      1.  
        Setting the environment variables for SF Sybase CE
      2. Starting or stopping SF Sybase CE on each node
        1.  
          Starting SF Sybase CE using the script-based installer
        2.  
          Starting SF Sybase CE manually on each node
        3.  
          Stopping SF Sybase CE using the script-based installer
        4.  
          Stopping SF Sybase CE manually on each node
      3.  
        Applying operating system updates on SF Sybase CE nodes
      4.  
        Adding storage to an SF Sybase CE cluster
      5.  
        Recovering from storage failure
      6.  
        Enhancing the performance of SF Sybase CE clusters
      7.  
        Verifying the nodes in an SF Sybase CE cluster
    2. Administering VCS
      1.  
        Viewing available Veritas device drivers
      2.  
        Starting and stopping VCS
      3.  
        Environment variables to start and stop VCS modules
      4.  
        Adding and removing LLT links
      5.  
        Configuring aggregated interfaces under LLT
      6.  
        Displaying the cluster details and LLT version for LLT links
      7.  
        Configuring destination-based load balancing for LLT
      8.  
        Enabling and disabling intelligent resource monitoring for agents manually
      9.  
        Administering the AMF kernel driver
    3. Administering I/O fencing
      1.  
        About administering I/O fencing
      2. About the vxfentsthdw utility
        1.  
          General guidelines for using the vxfentsthdw utility
        2.  
          About the vxfentsthdw command options
        3. Testing the coordinator disk group using the -c option of vxfentsthdw
          1.  
            Removing and replacing a failed disk
        4.  
          Performing non-destructive testing on the disks using the -r option
        5.  
          Testing the shared disks using the vxfentsthdw -m option
        6.  
          Testing the shared disks listed in a file using the vxfentsthdw -f option
        7.  
          Testing all the disks in a disk group using the vxfentsthdw -g option
        8.  
          Testing a disk with existing keys
      3. About the vxfenadm utility
        1.  
          About the I/O fencing registration key format
        2.  
          Displaying the I/O fencing registration keys
        3.  
          Verifying that the nodes see the same disk
      4. About the vxfenclearpre utility
        1.  
          Removing preexisting keys
      5. About the vxfenswap utility
        1.  
          Replacing I/O fencing coordinator disks when the cluster is online
        2.  
          Replacing the coordinator disk group in a cluster that is online
        3.  
          Refreshing lost keys on coordinator disks
      6.  
        Enabling or disabling the preferred fencing policy
      7.  
        About I/O fencing log files
    4. Administering CVM
      1.  
        Establishing CVM cluster membership manually
      2. Changing the CVM master manually
        1.  
          Errors during CVM master switching
      3.  
        Importing a shared disk group manually
      4.  
        Deporting a shared disk group manually
      5.  
        Verifying if CVM is running in an SF Sybase CE cluster
      6.  
        Verifying CVM membership state
      7.  
        Verifying the state of CVM shared disk groups
      8.  
        Verifying the activation mode
    5. Administering CFS
      1.  
        Adding CFS file systems to a VCS configuration
      2.  
        Uses of cfsmount to mount and cfsumount to unmount CFS file system
      3.  
        Resizing CFS file systems
      4.  
        Verifying the status of CFS file system nodes and their mount points
    6. Administering the Sybase agent
      1.  
        Sybase agent functions
      2.  
        Monitoring options for the Sybase agent
      3.  
        Using the IPC Cleanup feature for the Sybase agent
      4.  
        Configuring the service group Sybase using the command line
      5.  
        Bringing the Sybase service group online
      6.  
        Taking the Sybase service group offline
      7.  
        Modifying the Sybase service group configuration
      8.  
        Viewing the agent log for Sybase
  3. Troubleshooting SF Sybase CE
    1. About troubleshooting SF Sybase CE
      1. Gathering information from an SF Sybase CE cluster for support analysis
        1.  
          Gathering configuration information using SORT Data Collector
        2.  
          Gathering VCS information for support analysis
        3.  
          Gathering LLT and GAB information for support analysis
        4.  
          Gathering IMF information for support analysis
      2. SF Sybase CE log files
        1.  
          Collecting important CVM logs
      3.  
        About SF Sybase CE kernel and driver messages
      4. VCS message logging
        1.  
          GAB message logging
        2.  
          About debug log tags usage
        3.  
          Enabling debug logs for agents
        4.  
          Enabling debug logs for the VCS engine
        5.  
          Enabling debug logs for IMF
        6.  
          Message catalogs
      5. Troubleshooting tips
        1.  
          Sybase installation error log
        2.  
          Veritas log files
        3.  
          OS system log
        4.  
          GAB port membership
    2.  
      Restarting the installer after a failed network connection
    3.  
      Installer cannot create UUID for the cluster
    4. Troubleshooting I/O fencing
      1.  
        The vxfentsthdw utility fails when SCSI TEST UNIT READY command fails
      2.  
        Node is unable to join cluster while another node is being ejected
      3.  
        System panics to prevent potential data corruption
      4.  
        Cluster ID on the I/O fencing key of coordinator disk does not match the local cluster's ID
      5. Fencing startup reports preexisting split-brain
        1.  
          Clearing preexisting split-brain condition
      6.  
        Registered keys are lost on the coordinator disks
      7.  
        Replacing defective disks when the cluster is offline
    5. Troubleshooting Cluster Volume Manager in SF Sybase CE clusters
      1.  
        Restoring communication between host and disks after cable disconnection
      2.  
        Shared disk group cannot be imported in SF Sybase CE cluster
      3.  
        Error importing shared disk groups in SF Sybase CE cluster
      4.  
        Unable to start CVM in SF Sybase CE cluster
      5.  
        CVM group is not online after adding a node to the SF Sybase CE cluster
      6.  
        CVMVolDg not online even though CVMCluster is online in SF Sybase CE cluster
      7.  
        Shared disks not visible in SF Sybase CE cluster
    6. Troubleshooting interconnects
      1.  
        Network interfaces change their names after reboot
      2.  
        Example entries for mandatory devices
    7. Troubleshooting Sybase ASE CE
      1.  
        Sybase private networks
      2.  
        Sybase instances under VCS control
      3.  
        Node does not reboot
      4.  
        Sybase instance not starting
  4. Prevention and recovery strategies
    1. Prevention and recovery strategies
      1.  
        Verification of GAB ports in SF Sybase CE cluster
      2.  
        Examining GAB seed membership
      3.  
        Manual GAB membership seeding
      4.  
        Evaluating VCS I/O fencing ports
      5.  
        Verifying normal functioning of VCS I/O fencing
      6. Managing SCSI-3 PR keys in SF Sybase CE cluster
        1.  
          Evaluating the number of SCSI-3 PR keys on a coordinator LUN, if there are multiple paths to the LUN from the hosts
        2.  
          Detecting accidental SCSI-3 PR key removal from coordinator LUNs
      7.  
        Identifying a faulty coordinator LUN
      8.  
        Starting shared volumes manually
      9.  
        Listing all the CVM shared disks
      10.  
        I/O Fencing kernel logs
  5. Tunable parameters
    1. About GAB tunable parameters
      1.  
        About GAB load-time or static tunable parameters
      2.  
        About GAB run-time or dynamic tunable parameters
    2. About LLT tunable parameters
      1.  
        About LLT timer tunable parameters
      2.  
        About LLT flow control tunable parameters
      3.  
        Setting LLT timer tunable parameters
    3. About VXFEN tunable parameters
      1.  
        Configuring the VXFEN module parameters
  6. Appendix A. Error messages
    1.  
      About error messages
    2.  
      VxVM error messages
    3. VXFEN driver error messages
      1.  
        VXFEN driver informational message
      2.  
        Node ejection informational messages

How I/O fencing works in different event scenarios

Table: I/O fencing scenarios describes how I/O fencing works to prevent data corruption in different failure event scenarios. For each event, review the corrective operator actions.

Table: I/O fencing scenarios

Event

Node A: What happens?

Node B: What happens?

Operator action

Both private networks fail.

Node A races for majority of coordination points.

If Node A wins race for coordination points, Node A ejects Node B from the shared disks and continues.

Node B races for majority of coordination points.

If Node B loses the race for the coordination points, Node B panics and removes itself from the cluster.

When Node B is ejected from cluster, repair the private networks before attempting to bring Node B back.

Both private networks function again after event above.

Node A continues to work.

Node B has crashed. It cannot start the database since it is unable to write to the data disks.

Restart Node B after private networks are restored.

One private network fails.

Node A prints message about an IOFENCE on the console but continues.

Node B prints message about an IOFENCE on the console but continues.

Repair private network. After network is repaired, both nodes automatically use it.

Node A hangs.

Node A is extremely busy for some reason or is in the kernel debugger.

When Node A is no longer hung or in the kernel debugger, any queued writes to the data disks fail because Node A is ejected. When Node A receives message from GAB about being ejected, it panics and removes itself from the cluster.

Node B loses heartbeats with Node A, and races for a majority of coordination points.

Node B wins race for coordination points and ejects Node A from shared data disks.

Repair or debug the node that hangs and reboot the node to rejoin the cluster.

Nodes A and B and private networks lose power. Coordination points and data disks retain power.

Power returns to nodes and they restart, but private networks still have no power.

Node A restarts and I/O fencing driver (vxfen) detects Node B is registered with coordination points. The driver does not see Node B listed as member of cluster because private networks are down. This causes the I/O fencing device driver to prevent Node A from joining the cluster. Node A console displays:

Potentially a 
preexisting 
split brain. 
Dropping out 
of the cluster. 
Refer to the 
user 
documentation 
for steps 
required
to clear 
preexisting 
split brain.

Node B restarts and I/O fencing driver (vxfen) detects Node A is registered with coordination points. The driver does not see Node A listed as member of cluster because private networks are down. This causes the I/O fencing device driver to prevent Node B from joining the cluster. Node B console displays:

Potentially a 
preexisting 
split brain. 
Dropping out 
of the cluster. 
Refer to the 
user 
documentation 
for steps 
required
to clear 
preexisting 
split brain.

Resolve preexisting split-brain condition.

See Fencing startup reports preexisting split-brain.

Node A crashes while Node B is down. Node B comes up and Node A is still down.

Node A is crashed.

Node B restarts and detects Node A is registered with the coordination points. The driver does not see Node A listed as member of the cluster. The I/O fencing device driver prints message on console:

Potentially a 
preexisting 
split brain. 
Dropping out 
of the cluster. 
Refer to the 
user 
documentation 
for steps 
required
to clear 
preexisting 
split brain.

Resolve preexisting split-brain condition.

See Fencing startup reports preexisting split-brain.

The disk array containing two of the three coordination points is powered off.

No node leaves the cluster membership

Node A continues to operate as long as no nodes leave the cluster.

Node B continues to operate as long as no nodes leave the cluster.

Power on the failed disk array so that subsequent network partition does not cause cluster shutdown, or replace coordination points.

See Replacing I/O fencing coordinator disks when the cluster is online.

The disk array containing two of the three coordination points is powered off.

Node B gracefully leaves the cluster and the disk array is still powered off. Leaving gracefully implies a clean shutdown so that vxfen is properly unconfigured.

Node A continues to operate in the cluster.

Node B has left the cluster.

Power on the failed disk array so that subsequent network partition does not cause cluster shutdown, or replace coordination points.

See Replacing I/O fencing coordinator disks when the cluster is online.

The disk array containing two of the three coordination points is powered off.

Node B abruptly crashes or a network partition occurs between node A and node B, and the disk array is still powered off.

Node A races for a majority of coordination points. Node A fails because only one of the three coordination points is available. Node A panics and removes itself from the cluster.

Node B has left cluster due to crash or network partition.

Power on the failed disk array and restart I/O fencing driver to enable Node A to register with all coordination points, or replace coordination points.

See Replacing defective disks when the cluster is offline.