Sun Cluster Geographic Edition Data Replication Guide for Hitachi TrueCopy and Universal Replicator

Configuring Data Replication With Hitachi TrueCopy or Universal Replicator Software on the Primary Cluster

This section describes the tasks that you must perform on the primary cluster before you can configure Hitachi TrueCopy or Universal Replicator data replication in the Sun Cluster Geographic Edition software.

In all examples in this document, the “primary” cluster is the cluster on which the application data service is started during routine operations. The partner cluster is “secondary.” The primary cluster is named cluster-paris, and the secondary cluster is named cluster-newyork. The cluster-paris cluster consists of two nodes, phys-paris-1 and phys-paris-2. The cluster-newyork cluster also consists of two nodes, phys-newyork-1 and phys-newyork-2. Two device groups are configured on each cluster. The devgroup1 device group contains the paired devices pair1 and pair2. The devgroup2 device group contains the paired devices pair3 and pair4.

Configuration of the /etc/horcm.conf File

As used with the Sun Cluster Geographic Edition configuration, a Hitachi TrueCopy or Universal Replicator device group is a named entity consisting of sets of paired Logical Unit Numbers (LUNs). One member of each pair of LUNs is located in local storage on the primary cluster and the other member is located in local storage on a Sun Cluster Geographic Edition partner cluster. Data is written to one member of a pair of LUNs in local storage on the primary cluster and replicated to the other member of the pair on local storage on the secondary cluster. Each LUN in a pair is assigned the same name as the name that is assigned to the other LUN in the pair. Thus, data that is written to the LUN assigned the pair1 device name on the primary cluster is replicated to the LUN assigned the pair1 device name on the secondary cluster. Data that is written to the LUN assigned the pair2 device name on the primary cluster is replicated to the LUN assigned the pair2 device name on the secondary cluster.

On each storage-attached node of each cluster, pairs are given names and assigned to a device group in the /etc/horcm.conf file. Additionally, in this file, each device group is assigned a name that is the same on all storage-attached nodes of all clusters that are participating in a Sun Cluster Geographic Edition partnership.

In the /etc/horcm.conf file, you configure each Hitachi TrueCopy or Universal Replicator device group as a property of either the HORCM_DEV parameter or the HORCM_LDEV parameter. Depending on their intended use, you might configure one device group in the /etc/horcm.conf file as a property of HORCM_DEV and another device group as a property of HORCM_LDEV. However, a single device group can only be configured as a property of HORCM_DEV or of HORCM_LDEV. For any one device group, the selected parameter, HORCM_DEV or HORCM_LDEV, must be consistent on all storage-attached nodes of all clusters that are participating in the Sun Cluster Geographic Edition partnership.

Of the parameters that are configured in the /etc/horcm.conf file, only HORCM_DEV and HORCM_LDEV have requirements that are specific to the Sun Cluster Geographic Edition configuration. For information about configuring other parameters in the /etc/horcm.conf file, see the documentation for Hitachi TrueCopy and Universal Replicator.

Journal Volumes

Entries in the /etc/horcm.conf file for Hitachi Universal Replicator device groups can associate journal volumes with data LUNs. Journal volumes are specially configured LUNs on the storage system array. On both the primary and secondary arrays, local journal volumes store data that has been written to application data storage on the primary cluster, but not yet replicated to application data storage on the secondary cluster. Journal volumes thereby enable Hitachi Universal Replicator to maintain the consistency of data even if the connection between the paired clusters in a Sun Cluster Geographic Edition partnership temporarily fails. A journal volume can be used by more than one device group on the local cluster, but typically is assigned to just one device group. Hitachi TrueCopy does not support journaling.

If you want to implement journaling, you must configure Hitachi Universal Replicator device groups as properties of the HORCM_LDEV parameter because only that parameter supports the association of data LUNs with journal volumes in the Sun Cluster Geographic Edition Hitachi Universal Replicator module. If you configure Hitachi Universal Replicator device groups by using the HORCM_DEV parameter, no journaling occurs, and Hitachi Universal Replicator has no greater functionality than does Hitachi TrueCopy.

Configuring the /etc/horcm.conf File on the Nodes of the Primary Cluster

On each storage-attached node of the primary cluster, you configure Hitachi TrueCopy and Universal Replicator device groups as properties of the HORCM_DEV or HORCM_LDEV parameter in the /etc/horcm.conf file, and associate them with LUNs and, if appropriate, journal volumes. All devices that are configured in this file, including journal volumes, must be in locally attached storage. The /etc/horcm.conf file is read by the HORCM daemon when it starts, which occurs during reboot or when the Sun Cluster Geographic Edition software is started. If you change the /etc/horcm.conf file on any node after the Sun Cluster Geographic Edition software is started, and you do not anticipate rebooting, you must restart the HORCM daemon on that node by using the commands:


phys-paris-1# horcm-installation-directory/usr/bin/horcmshutdown.sh
phys-paris-1# horcm-installation-directory/usr/bin/horcmstart.sh

Table 1-2 shows the configuration of one journaling Hitachi Universal Replicator device group in the /etc/horcm.conf file as a property of the HORCM_LDEV parameter. Each LUN in the device group is described on a single line consisting of four space-delimited entries. The LUNs in the devgroup1 device group are named pair1 and pair2. The administrator chooses the device group and paired device names. In the third field of the file, each LUN is described by its serial number, followed by a colon, followed by the journal ID of its associated journal volume. In the logical device number (ldev) field, the controller unit (CU) is followed by a colon, which is followed by the logical device number. Both values are in hexadecimal format. All entries are supplied by the raidscan command, which is described in more detail in Hitachi's documentation. The ldev value that is supplied by the raidscan command is in decimal format, so you must convert the value to base 16 to obtain the correct format for the entry in the ldev field. You can only use the configuration shown in Table 1–2 with Hitachi Universal Replicator, as Hitachi TrueCopy does not support journaling.


Note –

If you want to ensure the consistency of replicated data with Hitachi Universal Replicator on both the primary cluster and the secondary cluster, you must specify a journal volume ID in the third property configuration field of HORCM_LDEV for each device in a Hitachi Universal Replicator device group. Otherwise, journaling does not occur and Hitachi Universal Replicator's functionality in Sun Cluster Geographic Edition configurations is no greater than the functionality of Hitachi TrueCopy.


Table 1–2 Example HORCM_LDEV Section of the /etc/horcm.conf File on the Primary Cluster

# dev_group

dev_name

serial#:jid#

ldev

devgroup1

pair1

10136:0

00:12

devgroup1

pair2

10136:0

00:13

Table 1–3 shows the configuration of one non-journaling Hitachi TrueCopy or Universal Replicator device group in the /etc/horcm.conf file as a property of the HORCM_DEV parameter. Each LUN in the device group is described on a single line consisting of five space-delimited entries. The table describes a device group named devgroup2 that is composed of two LUNs in a single shared storage array that is attached to the nodes of the primary cluster. The LUNs have the device names pair3 and pair4 and are designated by their port, CL1-A, target 0, and LU numbers, 3 and 4. The port number, target ID, and LU numbers are supplied by the raidscan command, which is described in more detail in Hitachi's documentation. For Hitachi TrueCopy and Universal Replicator, there is no entry in the MU number field.

Table 1–3 Example HORCM_DEV Section of the /etc/horcm.conf File on the Primary Cluster

# dev_group

dev_name

port number

TargetID

LU number

MU number

devgroup2

pair3

CL1-A

0

3

-

devgroup2

pair4

CL1-A

0

4

-

ProcedureHow to Set Up Raw-Disk Device Groups for Sun Cluster Geographic Edition Systems

Sun Cluster Geographic Edition supports the use of raw-disk device groups in addition to various volume managers. When you initially configure Sun Cluster, device groups are automatically configured for each raw device in the cluster. Use this procedure to reconfigure these automatically created device groups for use with Sun Cluster Geographic Edition.

  1. For the devices that you want to use, unconfigure the predefined device groups.

    The following commands remove the predefined device groups for d7 and d8.


    phys-paris-1# cldevicegroup disable dsk/d7 dsk/d8
    phys-paris-1# cldevicegroup offline dsk/d7 dsk/d8
    phys-paris-1# cldevicegroup delete dsk/d7 dsk/d8
    
  2. Create the new raw-disk device group, including the desired devices.

    Ensure that the new DID does not contain any slashes. The following command creates a global device group rawdg containing d7 and d8.


    phys-paris-1# cldevicegroup create -n phys-paris-1,phys-paris-2 \
    -t rawdisk -d d7,d8 rawdg
    

Example 1–1 Configuring a Raw-Disk Device Group

The following commands illustrate configuring the device group on the primary cluster, configuring the same device group on the partner cluster, and adding the group to a Hitachi TrueCopy or Universal Replicator protection group.


Remove the automatically created device groups from the primary cluster.
phys-paris-1# cldevicegroup disable dsk/d7 dsk/d8
phys-paris-1# cldevicegroup offline dsk/d7 dsk/d8
phys-paris-1# cldevicegroup delete dsk/d7 dsk/d8

Create the raw-disk device group on the primary cluster.
phys-paris-1# cldevicegroup create -n phys-paris-1,phys-paris-2 \
-t rawdisk -d d7,d8 rawdg

Remove the automatically created device groups from the partner cluster.
phys-newyork-1# cldevicegroup disable dsk/d5 dsk/d6
phys-newyork-1# cldevicegroup offline dsk/d5 dsk/d6
phys-newyork-1# cldevicegroup delete dsk/d5 dsk/d6

Create the raw-disk device group on the partner cluster.
phys-newyork-1# cldevicegroup create -n phys-newyork-1,phys-newyork-2 \
-t rawdisk -d d5,d6 rawdg

Add the raw-disk device group to the protection group rawpg.
phys-paris-1# geopg create -d truecopy -p Nodelist=phys-paris-1,phys-paris-2 \
-o Primary -p cluster_dgs=rawdg -s paris-newyork-ps rawpg

Next Steps

When configuring the partner cluster, create a raw-disk device group of the same name as the one you created here. See How to Replicate the Configuration Information From the Primary Cluster When Using Raw-Disk Device Groups for the instructions about this task.

Once you have configured the device group on both clusters, you can use the device group name wherever one is required in Sun Cluster Geographic Edition commands such as geopg.

How to Configure Veritas Volume Manager Volumes for Use With Hitachi TrueCopy Replication

If you intend to mirror data service storage by using Veritas Volume Manager, you must configure a Veritas Volume Manager disk group on the primary cluster containing the LUNs in a single Hitachi TrueCopy or Universal Replicator device group, and create a mirrored volume from those LUNs. For example, the previously configured pair1 device in the devgroup1 device group on the primary cluster is mirrored with the pair2 device in the devgroup1 device group on the primary cluster. See Configuration of the /etc/horcm.conf File and Configuring the /etc/horcm.conf File on the Nodes of the Primary Cluster. For details on the configuration of Veritas disk groups and volumes, see the Veritas Volume Manager documentation.

ProcedureHow to Configure the Sun Cluster Device Group That Is Controlled by Hitachi TrueCopy or Universal Replicator Software

Before You Begin

If you are using storage-based replication, do not configure a replicated volume as a quorum device. The Sun Cluster Geographic Edition software does not support Hitachi TrueCopy or Universal Replicator S-VOL and Command Device as a Sun Cluster quorum device. See Using Storage-Based Data Replication Within a Cluster in Sun Cluster System Administration Guide for Solaris OS for more information.

  1. Register the Veritas Volume Manager disk group that you previously configured.

    Use the Sun Cluster command cldevicegroup.

    For more information about this command, refer to the cldevicegroup(1CL) man page.

  2. Create a mount directory on each node of the cluster.


    phys-newyork-1# mkdir -p /mounts/sample
    phys-newyork-2# mkdir -p /mounts/sample
    
  3. Synchronize the Veritas Volume Manager configuration with Sun Cluster software, again by using the cldevicegroup command.

  4. After configuration is complete, verify the disk group registration.


    # cldevicegroup status
    

    The Veritas Volume Manager disk group, oradg1, should be displayed in the output.

    For more information about the cldevicegroup command, see the cldevicegroup(1CL) man page.

ProcedureHow to Configure a Highly Available File System for Hitachi TrueCopy or Universal Replicator Replication

Before You Begin

Before you configure the file system on cluster-paris, ensure that the Sun Cluster entities you require, such as application resource groups, device groups, and mount points, have already been configured.

If you are using storage-based replication, do not configure a replicated volume as a quorum device. The Sun Cluster Geographic Edition software does not support Hitachi TrueCopy or Universal Replicator S-VOL and Command Device as a Sun Cluster quorum device. See Using Storage-Based Data Replication Within a Cluster in Sun Cluster System Administration Guide for Solaris OS for more information.

  1. Create the required file system on the vol1 volume at the command line.

  2. Add an entry to the /etc/vfstab file that contains information such as the mount location.

    Whether the file system is to be mounted locally or globally depends on various factors, such as your performance requirements, or the type of application resource group you are using.


    Note –

    You must set the mount at boot field in this file to no. This value prevents the file system from mounting on the secondary cluster at cluster startup. Instead, the Sun Cluster software and the Sun Cluster Geographic Edition framework handle mounting the file system by using the HAStoragePlus resource when the application is brought online on the primary cluster. Data must not be mounted on the secondary cluster or data on the primary will not be replicated to the secondary cluster. Otherwise, the data will not be replicated from the primary cluster to the secondary cluster.


  3. Add the HAStoragePlus resource to the application resource group, apprg1.

    Adding the resource to the application resource group ensures that the necessary file systems are remounted before the application is brought online.

    For more information about the HAStoragePlus resource type, refer to the Sun Cluster Data Services Planning and Administration Guide for Solaris OS.


Example 1–2 Configuring a Highly Available Cluster Global File System

This example assumes that the apprg1 resource group already exists.

  1. Create a UNIX file system (UFS).


    phys-paris-1# newfs dev/vx/dsk/oradg1/vol1
    

    The following entry is created in the /etc/vfstab file:


    # /dev/vs/dsk/oradg1/vol1 /dev/vx/rdsk/oradg1/vol1 /mounts/sample \
    ufs 2 no logging
  2. Add the HAStoragePlus resource type.


    phys-paris-1# clresource create -g apprg1 -t SUNW.HAStoragePlus \
    -p FilesystemMountPoints=/mounts/sample -p Affinityon=TRUE \
    -p GlobalDevicePaths=oradg1 rs-has