VERITAS Volume Replicator (tm) 3.0 for Windows 2000 - Install

Article:TECH19477  |  Created: 2002-01-12  |  Updated: 2004-01-01  |  Article URL http://www.symantec.com/docs/TECH19477
Article Type
Technical Solution

Environment

Issue



VERITAS Volume Replicator (tm) 3.0 for Windows 2000 - Install

Solution



General Release Readme File
February 2002

This Readme file has the following topics:  
I. Requirements
II. Installing and Uninstalling the Programs
III. VVR Issues
IV. Documentation

I. REQUIREMENTS
Installation requirements or recommendations are:

- A system running Windows 2000 Server or Advanced Server with SP 1 or later, or Windows 2000 Data Center.

- At least 150 MB disk space for the Volume Manager and VERITAS Volume Replicator (VVR) together. The installer checks for disk space before installing.

- The system has at least 256 MB of memory.

- The monitor has a minimum resolution of 800 x 600 pixels. However if large fonts are used, (such as those enabled by the High Contrast option in the Control Panel's Accessibility Options window), a screen resolution of 1024 x 768 pixels or higher is recommended to properly display the text.

- The system should not be Dynamic Host Configuration Protocol (DHCP) enabled.

- To achieve good performance it is recommended to have a system with processor speed of 500 MHz or faster.

- For VVR, a minimum of two machines is needed, one as Primary and the other as Secondary, with a network connection between them.

II. INSTALLING AND UNINSTALLING THE PROGRAM

- It is HIGHLY recommended to exit all running applications prior to running the Volume Manager Setup program.

- Only one instance of Volume Manager should be running on the computer at a time. All previous versions of Volume Manager for Windows should be uninstalled before installing Volume Manager 3.0.

A. Initial Installation

If Volume Manager cluster disk groups are planned to be used with Microsoft Cluster Server (MSCS), make sure that MSCS is running on the target system when installing Volume Manager 3.0 (including VVR) for Windows 2000. For Volume Manager 3.0 for Windows 2000, VVR is an add-on license for Volume Manager Server and Advanced Server users. See the "Installing VVR" section in the VVR User's Guide, for more details on installing VVR.

B. Uninstalling the Program

See the "Uninstalling VVR" section in the VVR User's Guide for more details on installing VVR.

III. VVR ISSUES

A. Related to Volume Manager Operations

Note: VVR is supported only with Volume Manager 3.0 current-version disk groups. If you are upgrading from an earlier version of Volume Manager and have existing disk groups, those disk groups must be upgraded to Volume Manager 3.0 current version disk groups. See the section "Upgrading a Dynamic Group Version" in the Volume Manager 3.0 for Windows 2000 User's Guide.

1. Resizing the data volumes under a Replicated Volume Group (RVG) on the Primary could give a misleading message (Incident 70724).

On resizing the data volumes on the Primary, an error message "Cannot open volume handle" is displayed. This message could be misleading since the operation of resizing the data volumes does succeed. When only the data volume on the Primary is grown, the replication state of the Secondary becomes "Secondary Paused" because of the mismatch between primary data volume and corresponding secondary data volume.

It is recommended to plan the replication environment in advance and refrain from resizing the data volumes at a later stage. However, in the event that the data volumes must be resized under an RVG, do the following:

a. Check that on all Secondaries and the primary, the data volume can be grown to the new desired size.
b. Resize the corresponding volume on all the Secondaries, such that these have the same size on all Secondaries.
c. If resizing the corresponding data volumes on all Secondaries is successful, resize the volume on Primary.

All the data volumes must be of identical size at the end of the operation for VVR to continue operation successfully.

2. Renaming of a disk group (Incident 69573).

Do not rename a disk group that has VVR objects. The disk group name of the Primary RVG and Secondary RVG is required to be identical.

3. Offlining a disk group with VVR Objects (Incident 70960).

Do not offline a Disk Group with VVR Objects. This results in the Primary and the Secondary getting detached causing replication to stop.

4. Volumes with Volume Manager Dirty Region Log (DRL) cannot be added under RVG. For volumes configured for replication, DRL is not used and hence not required. VVR recovery ensures that the data volumes are correctly recovered. To use any volumes having DRL for replication, remove the DRL using the Log > Delete command for the volume. The volume is then available to be added using the Add Volume Wizard.

B. Related to VVR Operations

1. If Primary host is down or if VERITAS Object Bus service on Primary is not started, the delete Secondary operation fails (Incident 67731).

In this case, restart the Primary OR the VERITAS Object Bus Service, if possible. Delete Secondary operation can then be successfully performed.

Alternatively, remove the Volumes and the Replicator Log from the Secondary RVG by issuing the Remove Volume and Dissociate Replicator Log command, respectively. The Delete Secondary operation can then be successfully performed.

2. Data should not be copied on Replicator Log volume (Incident 71354).

When a volume with a file system is added under RVG as Replicator Log, the file system format is lost, making it a RAW volume. The file system is not aware of this immediately. The writes from the file system to the Replicator Log volume are not actually written to the volume and eventually the file system reports "Delayed Write Failure" on the Replicator Log volume.

3. Adding a mirror to a data volume with DCM Log may fail.(Incident 71668).

Adding extra disks in the disk group will resolve the problem.

4. Using VPN (Virtual Private Network) as a replication network for VVR.(Incident 91502).

The VVR 3.0 on Windows 2000 cannot create a Replicated Data Set (RDS) that consists of primary or secondary hosts that have been configured to use VPN for replication. This is because VVR 3.0 on Windows 2000 does not support the volume replication through VPN.

Avoid using the VPN and DHCP enabled networks as a replication network for VVR replication.

5. In MSCS environment, the virtual SQL server hangs the cluster server while creating user database on replicated volume of clustered primary RVG (Incident 91520).

When both VVR primary RVG (Replicated Volume Group) and Microsoft (virtual) SQL server are configured under the MSCS cluster, and SQL server resource has a dependency on RVG resource. With this configuration, creating a user database or attaching an existing user database to the SQL server, may cause the create database or attach database command to hang. It will also hang the cluster commands or GUI.

The virtual SQL server always consults the cluster server while creating or attaching a database to ensure that the volumes of the database are covered under the cluster and hence those can be shared within a cluster. To verify this, the SQL server generates a query (for the supported volumes) to every cluster storage class resource on which its resource is configured as a dependent resource under cluster.

Just like the "Physical Disk" and "Volume Manager Disk Group", the VVR RVG is also a storage class resource. The RVG resource represents all the data volumes within its parent cluster Disk Group as supported volumes for the query.

To support the query for volumes, the RVG resource requires making a cluster API call, which is of type LPC/RPC (local or remote inter-process call). On most of the setups, this LPC/RPC (cluster API) works fine, however on some setups, due to some (not yet identified) reasons, the cluster API hangs causing both cluster and SQL server to suspend its operations. Either some specific system configurations or some internal bug in LPC/RPC support are among the suspected reasons of the RPC/LPC (Cluster API) hang.

This issue occurs rarely only on certain specific setups. However, we recommend that while creating the RVG resource instance (particularly for SQL server user database replication), select the "Run this resource in a separate Resource Monitor" check box, on the first page of "Create Resource" wizard. For already existing RVG resources, this can be set through resource properties and then take the resource offline and later bring it online.

If the SQL server and cluster hangs during database create/attach operations, even before applying the above mentioned workaround, a quick and safe way to recover from it is to terminate the resource monitor process(s) running on the cluster node on which the cluster group of SQL server and VVR RVG resources reside. To terminate the resource monitor process, use the "Task Manager"; select the resrcmon process instance(s) from the "Processes" tab and press "End Process" button.

C. VVR Limitations

1. Dynamic Group Split and Join Operations are not supported with VVR.

2. Error message "Delayed Write Failed"

This error occurs if the data volume is mounted with a FAT, FAT32, or NTFS file system. The message is displayed by the file system. If the connection between the Primary and a Secondary in synchronous mode is broken, the file system cache flush operation (deemed as a write operation for VVR) on the data volume fails. This causes the file system to display the error message "Delayed Write Failed."

3. Data written to Secondary volumes does not always show up immediately.

When VVR writes data onto the Secondary volumes, the file system does not reflect this immediately if the volume is already mounted. If the volume is remounted, the file system on the volume updates its metadata, thus reflecting the correct replicated contents of the file system.

4. Deleting RDS having two Secondaries may fail with the error "A Secondary host has to be specified."

The workaround is to delete one of the Secondaries by using the command Delete Secondary and then try the Delete RDS command again.

5. The Associate Replicator Log and Add/Remove DCM Log commands should be performed for an RVG from the VM console connected to the host of that RVG only.

6. The Add Volume command should preferably be invoked from the Primary host. If it is invoked from Secondary, do not use the Add DCM command. The DCM Log will be added to the volumes on the Secondary side.

7. Trying to reassign the drive letter on the Secondary data volume sometimes makes the file system report that chkdsk is required to be run on the volume. This error is harmless, and the volume can be explored without any problems.

8. The Replicator Log volume must not be resized.

9. A DHCP-configured host must not be used as VVR primary or Secondary.

10. Do not connect to the VEA console as localhost when creating RDS. Use the host name or for host with multiple IPs use the specific IP you want to use for replication."

11. Secondary looses connection with the Primary after long period of stressing when NAV, (Norton AntiVirus), is installed and virus scans are scheduled on Primary host.

When Norton AntiVirus is installed on the VVR host with the primary RVG, after several hours of usage, specifically after few antivirus scans, the VVR host would experience a system freeze, hang or would be extremely slow in responding to user interactions. This could also result in changes in behavior of the VVR replication services, such as secondary disconnection or loss of data.

Also, it has been observed that when Norton AntiVirus is scanning the server for virus detection with VVR enabled and having heavy workload, a similar stress condition is triggered. This is because of the known issue with a few versions of Norton AntiVirus (including Corporate Edition, version 7.0x) that causes kernel memory leaks during its virus scans. Such kernel memory leaks would severely degrade the system performance causing the system to become unstable, slow in responding, and in some cases may even cause a system crash.

When such a situation occurs, restarting the system is the only way to recover.

We recommend that the administrators schedule NAV scans at times when VVR/application workload is lean, to avoid this problem.

The Symantec Corporation (makers of Norton AntiVirus) has acknowledged the kernel memory leak issues in the Corporate Edition (program version 7.0x), reference: Document ID: 2001011809064548, Release Notes: for edition 7.51. The release notes mention memory leak fixes. However, as of now, the VVR is not fully tested with edition 7.51 to verify that it is completely free from kernel memory leaks.

IV. DOCUMENTATION

This section summarizes the documentation included with the Volume Manager 3.0 for Windows 2000 GA release.

The documentation consists of:

1. Online Help -
To bring up the online help, select Contents from the Help menu. The Volume Manager 3.0 help is at the bottom of the tree view on the left pane of the help window. If VVR is installed, the VVR node should display above the Volume Manager node in the tree view. The additional nodes refer to VEA help, the VERITAS Integration Platform help for the main VERITAS Enterprise Administrator GUI.

2. Volume Replicator 3.0 for Windows 2000 User's Guide -
The main manual for Volume Replicator (VVR).

3. Volume Replicator 3.0 for Windows 2000 Release Notes -
This small manual gives a summary of the program and includes information on requirements and documentation.

4. This readme file -
The readme file includes VVR information.

5. Highly Available VERITAS Volume Replicator 3.0 for Windows 2000 using Microsoft Cluster Server -
This document provides information, procedures and guidelines for configuring and administering the High Availability solution of VVR using MSCS.

6. Using VERITAS Volume Replicator for Disaster Recovery of a SQL Server -
This document provides information on using VVR to implement disaster recovery procedures on a SQL server.


Attachments

VVR2K30ENU_246348.exe (61.5 MBytes)

Supplemental Materials

SourceiTools
Value69573
DescriptionRename causes the Primary RVG node to disappear from the treeview.

SourceiTools
Value67731
DescriptionIf the Primary of a RDS goes down, the objects of the Secondary cannot be removed.

SourceiTools
Value70724
DescriptionResize of a volume (on Primary ) that is a part of an RDS should not be allowed.

SourceiTools
Value70960
DescriptionOfflining a disk that is a part of the RDS causes the Primary & secondary to be permanently detached.

SourceiTools
Value71345
DescriptionData can be copied on to the SRL volumes.

SourceiTools
Value71668
DescriptionCan't mirror a data volume.

SourceiTools
Value91502
DescriptionCan't add Secondary over VPN, Secondary already in RDS message pops up.

SourceiTools
Value91520
DescriptionCan't create a SQL DB using SQL Analyzer in an MSCS environment where VVR is replicating on a private network.


Legacy ID



246348


Article URL http://www.symantec.com/docs/TECH19477


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