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ETERNUS SF AdvancedCopy Manager 14.1 Operator's Guide

11.1.1 General notes

This section provides general notes on backup and replication.

11.1.1.1 Storage Server locale

The locale (software localisation information) of the internal code system (the code system specified when AdvancedCopy Manager is installed on the Storage Management Server) used by AdvancedCopy Manager must be installed on all Storage Servers.
Action is required if there are differences between the language environments (LANG) of the Storage Management Server and the Storage Servers. The following table shows the actions required for various combinations:

Table 11.1 Storage Management Server and Storage Server language environment combinations

Storage Management Server

Storage Server

Action required

Windows (SJIS)

Windows (SJIS)

None

Solaris (EUC)

Install the SJIS package on the Storage Server.

HP-UX (EUC)

Install the SJIS package on the Storage Server.

Linux (EUC)

None

Linux (UTF8)

None

AIX (SJIS)

None

AIX (EUC)

Add the SJIS language environment on the Storage Server.

In accordance with the Solaris locale setting (standard: EUC)

Windows (SJIS)

None. (If the Storage Management Server is EUC, Storage Server processing is problem free.)

Solaris (EUC)

None (if the code is the same).

If the Management Server is SJIS, install the SJIS package on the Storage Server.

HP-UX (EUC)

None (if LANG is the same).

If the Management Server is SJIS, install the SJIS package on the Storage Server.

Linux (EUC)

None

Linux (UTF8)

None

AIX (SJIS)

None (if LANG is the same).

If the Management Server is EUC, add the EUC language environment.

AIX (EUC)

None (if LANG is the same).

If the Management Server is SJIS, add the SJIS language environment.

Linux (EUC)

Windows (SJIS)

None. (If the Storage Management Server is EUC, Storage Server processing is problem free.)

Solaris (EUC)

None

HP-UX (EUC)

None

Linux (EUC)

None

Linux (UTF8)

None

AIX (SJIS)

Add the EUC language environment on the Storage Server.

AIX (EUC)

None

Linux (UTF8)

Windows (SJIS)

None

Solaris (EUC)

Add the UTF8 language environment on the Storage Server.

HP-UX (EUC)

Add the UTF8 language environment on the Storage Server.

Linux (EUC)

None

Linux (UTF8)

None

AIX (SJIS)

Add the UTF8 language environment on the Storage Server.

AIX (EUC)

Add the UTF8 language environment on the Storage Server.

After the appropriate package is installed, re-execute the "Update information of all devices at the Storage Server" operation at the GUI client.

11.1.1.2 Size of a Partition

A transaction volume and a backup volume must have the same size.

However, not all of the size specified by the fdisk command will be usable for the following disks because the OS control space is automatically allocated.

Figure 11.1 Available Size of a Partition

Create partitions for the transaction and backup volumes in the same size and combination as shown below.

Figure 11.2 Combination of Transaction and Backup Volume

Figure 11.3 Example of a Disk with Partitions of Different Sizes

If you are creating the source and destination volumes in the same size for replication, create partitions in the combination as shown above.

Point

To prevent an operational error, you are recommended to define as extended logical disks all the logical disks on the ETERNUS disk storage systems to be managed by AdvancedCopy Manager.
If you cannot define all the logical disks as extended logical disks, you are recommended to use the same configuration for a partition, including a device defined as a transaction volume and a partition with a device defined as a backup volume.

Note

To back up a PRIMECLUSTER GDS volume

To backup a GDS volume, specify the sector size to set a backup volume size that matches the GDS volume.
Create the backup volume as follows:

  1. Find out the accurate size and number of the GDS volumes to be backed up.
    The accurate size is obtained by multiplying the number of blocks output by the following command by 512 bytes.

    sdxinfo -o volume-name

    In the following example, 425984 is output as the number of blocks. Therefore, the size is 218103808 bytes (425984 blocks x 512).

    # sdxinfo   -o v1
    OBJ    NAME    CLASS   GROUP   SKIP JRM 1STBLK   LASTBLK  BLOCKS   STATUS
    ------ ------- ------- ------- ---- --- -------- -------- -------- --------
    volume v1      c1      g1      off  on     65536   491519   425984 ACTIVE
  2. Use the parted command to check that the disk format of the backup volume is msdos. If the format is not msdos, execute "/sbin/parted <device name> mklabel msdos" to format as msdos.

  3. Find out the number of bytes in each sector of the disk where the backup volume is to be created.

    In the following example, "sectors of 512 bytes" indicates that the size of each sector is 512 bytes.

    # /sbin/sfdisk -uS -l /dev/sdp
    Disk /dev/sdp: 1017 cylinders, 133 heads, 62 sectors/track
    Units = sectors of 512 bytes, counting from 0
    
    Device Boot    Start       End   #sectors  Id  System
    /dev/sdp1             0         -          0   0  Empty
    /dev/sdp2             0         -          0   0  Empty
    /dev/sdp3             0         -          0   0  Empty
    /dev/sdp4             0         -          0   0  Empty

    The following error is returned if the disk does not have an msdos disk label:

    "sfdisk: ERROR: sector 0 does not have an msdos signature"

    Use the fdisk command or the parted command in advance to create an msdos disk label on the targeted disk.

    Example: Use the # parted command to create an msdos disk label.

    # /sbin/parted /dev/sdp mklabel msdos
  4. Calculate the number of sectors in the backup volume being created.

    218103808 bytes / 512 bytes = 425984 sectors

    However, the partition descriptor is located in the first sector of a logical volume, so this sector cannot be used. Therefore, add one sector to the number of sectors obtained in this calculation.

    425984 sectors + 1 = 425985 sectors

    Thus, the number of sectors to create is 425985.

  5. Use the sfdisk command to create the files to be input.
    Since files need to be created as logical partitions in extension partitions in a backup volume, files like the following are created:

    # cat ./sdp-partition.dat
    ,,E
    ;
    ;
    ;
    ,128,L
    ,425985,L
    ,425985,L
    ,425985,L

    The first logical partition (/dev/sdp5) cannot be made the same size as the other logical partitions for reasons related to partition descriptors.
    Therefore, the first logical partition is created to be the appropriate size (in this case, 128 sectors) and is not used as part of the backup volume.

  6. Use the sfdisk command to create the partitions.

    #  /sbin/sfdisk -uS --force /dev/sdp < ./sdp-partition.dat
    Checking that no-one is using this disk right now ...
    OK
    
    Disk /dev/sdp: 1017 cylinders, 133 heads, 62 sectors/track
    Old situation:
    Units = sectors of 512 bytes, counting from 0
    
       Device Boot    Start       End   #sectors  Id  System
    /dev/sdp1             0         -          0   0  Empty
    /dev/sdp2             0         -          0   0  Empty
    /dev/sdp3             0         -          0   0  Empty
    /dev/sdp4             0         -          0   0  Empty
    New situation:
    Units = sectors of 512 bytes, counting from 0
    
       Device Boot    Start       End   #sectors  Id  System
    /dev/sdp1             1   8386181    8386181   5  Extended
    /dev/sdp2             0         -          0   0  Empty
    /dev/sdp3             0         -          0   0  Empty
    /dev/sdp4             0         -          0   0  Empty
    /dev/sdp5             2       129        128  83  Linux
    /dev/sdp6           131    426114     425984  83  Linux
    /dev/sdp7        426116    852099     425984  83  Linux
    /dev/sdp8        852101   1278084     425984  83  Linux
    Warning: partition 5 does not end at a cylinder boundary
    Successfully wrote the new partition table
    
    Re-reading the partition table ...
    
    If you created or changed a DOS partition, /dev/foo7, say, then use dd(1)
    to zero the first 512 bytes:  dd if=/dev/zero of=/dev/foo7 bs=512 count=1
    (See fdisk(8).)

    Use the created /dev/sdp6, /dev/sdp7, and /dev/sdp8 as the backup volume.

11.1.1.3 Backup and Replication Exclusions

The following devices must not be backed up or replicated:

11.1.1.4 Consistency of data on volumes

Table 11.2 Consistency of data on volumes

Data in transaction volume

Maintenance of data integrity

Operation

Oracle database space being used

Linkage with Oracle is required.

Use a sample script designed for linkage with Oracle.

For details, refer to Appendix B Sample Script for Backup Operations.

File system

A AdvancedCopy Manager command unmounts the file system to maintain the integrity.

Refer to "Appendix A Pre-processing and Post-processing of Backup and Restoration", and "Appendix C Pre-processing and Post-processing of Replication".

Other than the above

The data integrity must be maintained in operations.

Take appropriate action, such as stopping transactions during execution of backup or replication.

11.1.1.5 Fetching Device Information

Before starting either the backup or replication operation, 4.4.5 Fetching device information on a Storage Server that is managed by all the Storage Servers using the GUI client of AdvancedCopy Manager. The time taken to complete this operation is proportional to the total number of devices defined on the selected storage servers. If many devices are involved, perform this operation while the CPU or I/O load on the system is low.

As a guide, about 0.5 seconds are required per device (i.e., partition) when there is no load on the system.

11.1.1.6 Maximum Number of Simultaneously Executing Operations

An upper limit (maximum value) applies to the number of Advanced Copy sessions in one LU (Logical Unit) that can be executed simultaneously. Ensure the number of volumes in one LU is the same or less than the maximum number of copy sessions per LU.

If a greater number of volumes than the maximum number of copy sessions per LU needs to be created in the LU for operational reasons, operations must be designed to prevent simultaneous execution of more than the maximum number of Advanced Copy sessions to volumes in the same LU.

Refer to the ETERNUS disk storage systems SA/SE Handbook for the maximum number of copy sessions per LU.

11.1.1.7 Mounting of disks from other servers

Before backup/restoration or replication of a volume that can be mounted from multiple servers, cancel all mounting from the other servers.

For disks that need not be mounted from other servers, prevent multiple servers from detecting or accessing the same partition by setting up hardware, such as devices in the ETERNUS disk storage systems and Fibre Channel switches, accordingly.

11.1.1.8 Notes on copy operations targeted at file systems

For a copy operation targeted at a file system, unmount the relevant volume to prevent data access and maintain the data integrity.
If backup/restoration and replication are performed without unmounting the volume, an error occurs since a volume in use cannot be unmounted.

Note the following about processing where unmounting is enabled:

Unmounting is required only during command execution. Normal operations can be resumed after command execution.

11.1.1.9 Mirroring in GDS

For cabinet-to-cabinet mirroring, both systems of the mirroring must be backed up if restoration is required by OPC in the event of a cabinet failure. In these cases, the size of the backup volume must be a physical volume size, not logical volume size.

11.1.1.10 Notes on executing Logical Unit (disk) unit copy

Logical Unit (disk unit) copy can be used for replication operations.
Note the following points if Logical Unit (disk unit) copy is executed:

Tape backup

Refer to "System volume backup and restore" in the "ETERNUS SF AdvancedCopy Manager Operator's Guide for Tape Backup" for details of the tape backup functions.

Inter-server copy

Both servers must run Version 13.1 or later.

Copying between Logical Units (disks) of different sizes

When copying between Logical Units (disks) of different sizes, the physical copy matches the size of the smaller Logical Unit (disk). If the copy direction is from the smaller Logical Unit (disk) to the larger Logical Unit (disk), part of the area on the larger disk is not physically copied to, and data from before the copy operation remains. If this remaining area contains the Logical Unit (disk) management information, partitioning tools may identify the disk format incorrectly. Therefore, format the copy destination Logical Unit (disk) before copying to it.

Notes when executing copy
  • If the replication source/destination volume areas for replication management, and the transaction/backup volume areas for backup management duplicate each other, replication management and backup management operations cannot be performed simultaneously for volumes that have duplicate areas.

  • Execute copy operations when the partitions included in the Logical Unit (disk) are in the unmounted state. If copy is executed when the partitions are in the mounted state, the partitions included in the copy destination disk may not be able to be made consistent as a file system.

SDX objects

Logical Unit (disk unit) copying cannot be used for SDX objects.

11.1.1.11 Notes on executing copy between different operating systems

Copies can be made between different operating systems by using replication operations.
Use the following combinations to execute copy between different operating systems:

Table 11.3 Combinations for executing copy between different operating systems

Copy destination

slices

Logical Unit (disk)

Copy source

Partition

Y

N

Logical Unit (disk)

Y

ZN

Y: Possible
N: Not possible

Note

SnapOPC+ cannot be used with the following operating systems:

  • Red Hat Enterprise Linux AS (v.3 for x86)

  • Red Hat Enterprise Linux ES (v.3 for x86)

If SnapOPC+ is to be used for executing copy operations between different operating systems, perform copy between operating systems that can use SnapOPC+.

11.1.1.12 Supported disk formats

The following disk formats are supported:

Table 11.4 Supported disk formats

Support OS

Disk format

GPT

MBR

Red Hat Enterprise Linux AS (v.3 for x86)
Red Hat Enterprise Linux ES (v.3 for x86)

N

R

Red Hat Enterprise Linux AS (v.4 for x86)
Red Hat Enterprise Linux ES (v.4 for x86)
Red Hat Enterprise Linux (v.5 for x86)

Y

R

Red Hat Enterprise Linux AS (v.4 for EM64T)
Red Hat Enterprise Linux ES (v.4 for EM64T)
Red Hat Enterprise Linux (v.5 for EM64T)

Y

R

Red Hat Enterprise Linux AS (v.4 for Itanium)
Red Hat Enterprise Linux (v.5 for Intel Itanium)

R

Y

R: Supported (recommended)
Y: Supported
N: Not supported

11.1.1.13 Operations that use the device names (by-id and by-path) generated by the udev facility

Note the following points if AdvancedCopy Manager operations use device names generated by the udev facility.
The device names used when a file system is mounted must be the same as the device names used by AdvancedCopy Manager.

11.1.1.14 Notes when using the -m option

When replication occurs between servers, the -m option can be specified in the following commands in order to avoid communication processing to non-operating servers:

When the -m option is specified, any one of the following conditions must apply in order to ensure that problems do not arise as a result of not performing volume pre-processing and post-processing at the non-operating server:

  1. The non-operating server has been shut down.

  2. Manual pre-processing and post-processing is performed for the volumes on the non-operating server.

  3. The target volume is a RAW device (Oracle, etc., that does not need pre-processing and post-processing), rather than a file system.

11.1.1.15 Copy processing performance of Advanced Copy

The Advanced Copy processing is performed by the ETERNUS disk storage systems. Therefore, direct enquiries concerning copy processing performance to the support department for the ETERNUS disk storage systems.

11.1.1.16 Mount by Label

In the case where a source volume has a filesystem label and where the following conditions hold, Advanced Copy can cause the status where multiple volumes with the same label exist in one system.

  1. Backup/restore or replication within a server is employed.

  2. Replication between servers is employed and a volume in the destination server has the same label as a source volume.

When there are multiple volumes with the same label, processing such as mount may not work correctly.
To avoid this phenomenon, specify not a label but a device (e.g. /dev/sda1) for /etc/grub.conf and /etc/fstab.