Performing an External Backup

The database server must be online or in quiescent mode during an external backup.

Performing an External Backup when Chunks are not Mirrored

To obtain an external backup, block the database server. The system takes a checkpoint and suspends all update transactions. Users can access the database server in read-only mode.
Dynamic Server
On Dynamic Server, use the following command:
```
onmode -c block
```
End of Dynamic Server

Extended Parallel Server
On Extended Parallel Server, use the following command to block all the coservers in cogroup_all:
```
onutil ebr block;
```
End of Extended Parallel Server
To back up the storage spaces and administrative files, use a copy command, such as cp, dd, or tar on UNIX or copy on Windows, or a file-backup program. You must back up all chunks in the storage spaces.
To allow normal operations to resume, unblock the database server.
Dynamic Server
Use the following command:
```
onmode -c unblock
```
End of Dynamic Server

Extended Parallel Server
Use the following command to unblock all the coservers in cogroup_all and mark all dbspaces on each coserver as having a level-0 backup:
```
onutil ebr unblock commit;
```
End of Extended Parallel Server
Back up all the logical logs including the current log so that checkpoint information is available for the external restore.
Warning:

Because external backup is not done through ON–Bar, you must ensure that you have a backup of the current logical log from the time when you execute the onutil EBR BLOCK or onmode -c block command. Without a backup of this logical-log file, the external backup is not restorable.
After you perform an external backup, back up the current log.
Dynamic Server
Use the following command to back up the current log on Dynamic Server:
```
onbar -b -l -c
```
End of Dynamic Server

Extended Parallel Server
Use the following commands to switch to and back up the current log on Extended Parallel Server:
```
onmode -l   # execute on coservers with external backups
onbar -b -l # back up all used logs
```
End of Extended Parallel Server

If you lose a disk, coserver, or the whole system, you are now ready to perform an external restore.

Performing an External Backup when Chunks are Mirrored by the Database Server (XPS)

When you use the mirroring support provided by the database server, you should create your backups by copying the data from the primary chunks to make tracking your backups easier. Mirroring is configured using the MIRROR configuration parameter in the ONCONFIG file. For more information on mirroring, see the chapter on mirroring in the IBM Informix: Administrator's Guide.

To perform an external backup when chunks are mirrored

To obtain an external backup, block the database server. The system takes a checkpoint and suspends all update transactions. Users can access the database server in read-only mode.
On Extended Parallel Server, use the following command to block all the coservers in cogroup_all:
```
onutil ebr block;
```
To back up the storage spaces and administrative files, use a copy command, such as cp, dd, or tar on UNIX or copy on Windows, or a file-backup program. You must back up all chunks in the primary storage spaces. Do not backup mirror chunks.
To allow normal operations to resume, unblock the database server.
Use the following command to unblock all the coservers in cogroup_all and mark all dbspaces on each coserver as having a level-0 backup:
```
onutil ebr unblock commit;
```
Back up all the logical logs including the current log so that checkpoint information is available for the external restore.
Warning:

Because external backup is not done through ON–Bar, you must ensure that you have a backup of the current logical log from the time when you execute the onutil EBR BLOCK or onmode -c block command. Without a backup of this logical-log file, the external backup is not restorable.
After you perform an external backup, back up the current log.
Use the following commands to switch to and back up the current log on Extended Parallel Server:
```
onmode -l   # execute on coservers with external backups
onbar -b -l # back up all used logs
```

Performing an External Backup Using Third-Party Mirroring Solutions (XPS)

When you mirror your data using third-party mirroring solutions provided by the hardware or the operating system, it might be possible to backup the chunks in your dbspaces using third-party mirror maintenance commands provided by such mirroring solutions instead of relying on commands such as cp, dd, or tar on UNIX, or copy on Windows. This section outlines a procedure for performing external backups using third-party mirror maintenance commands, based on the idea of using your chunk mirrors as your backups.

To perform an external backup using third-party mirroring solutions

Copy the primary partition to the mirror partition.
Synchronize the mirrored disk partitions.
Block the database server. The system takes a checkpoint and suspends all update transactions.
Break the link between the disk mirrors. If needed, install a new set of disk mirrors.
Unblock the database server so that transactions can resume.
Back up the logical logs.
Put the mirror disk into storage, copy the mirrored data to another computer, or back it up to tape or storage media by using a file-system backup program or an operating-system copy command.
Reconnect and synchronize the disk mirrors, if necessary.

You could use this technique to set up a high-availability environment and use external backups for fail-over to a second database server.