Mirroring and Duplexing Partitions

The process for mirroring and duplexing is the same. The term mirroring is used in all menus to refer to both mirroring and duplexing.

The following procedures explain how to mirror and unmirror NetWare partitions and how to recover data when partitions are no longer mirrored:

Mirroring Partitions

IMPORTANT: If you want to mirror IDE/ATA disks, you should duplex them by mirroring them on separate host adapters or on different ports of a multiport IDE/ATA host adapter, with each port or adapter configured to support a single drive. This is necessary because IDE drives have a design limitation that prevents them from continuing normally after one of the drives fails.

Note that mirroring can take a long time to complete, depending on the size of the partitions and the amount of data to be mirrored. To mirror one or more NetWare partitions to each other, follow these steps.

Prerequisites

A disk containing one or more partitions with data you want to mirror
A blank disk to contain the mirrored data from the first disk
Hot Fix enabled on all partitions

Procedure

Make sure all partitions are deleted from the disk that will be mirrored to an existing disk.

Make sure you do not delete the partitions from the disk containing data you want to mirror. If you need help deleting partitions, see Deleting NetWare Partitions.
On the blank disk, create one or more new partitions to match those on the disk containing data. Do not create any volumes.

If you need help, see Creating NetWare Partitions. Be sure to enable Hot Fix on the new partitions.

Make the data area of the new partitions the same size in blocks as the data area of the partitions containing information. When you mirror the partitions, the partitions containing information will be mirrored to the new partitions.
Load NWCONFIG and select Standard Disk Options.

From the Available Disk Options menu, select Mirror/Unmirror Disk Partitions.

A Disk Partition Mirroring Status window appears. This window lists each device and its mirrored status. For example,

Mirrored: Logical Partition 7

Not Mirrored: Logical Partition 3

Out of Sync: Logical Partition 6

The meaning of each status is as follows:

Status Explanation
Mirrored

The partition is mirrored to another partition.

Not Mirrored

The partition is not mirrored to another partition.

Out of Sync

The partition is mirrored to another partition, but is currently out of sync.

From the Disk Partition Mirroring Status window, select the disk partition containing live data you want to mirror to another partition.

A Mirrored Disk Partitions list appears. This window displays any hard disks that are currently mirrored to the partition you selected.

You must now specify the empty partition to be mirrored to the selected partition.
Press Insert.

The system displays the Available Disk Partitions list---a list of all partitions that can be mirrored to the first partition.

IMPORTANT: Do not mirror one NetWare partition to another NetWare partition on the same disk. To do so eliminates fault tolerance.
Select the empty partition from the Available Disk Partitions list.

The system mirrors the two partitions to each other so that one partition becomes synchronized with the data from the other partition.

Mirroring can take a long time, depending on the size of the partitions and the amount of data to be mirrored. You can view the status of mirroring, abort the mirroring, and start the mirroring again, by entering the following commands at the server console:
- MIRROR STATUS
  Displays a list of logical partitions and their mirroring status, such as Being Remirrored. If a partition is being mirrored, the percent complete is also displayed. See Reference > Utilities Reference.
- ABORT REMIRROR logical_partition_number
  Stops the mirroring process on a designated partition. See Reference > Utilities Reference > Utilities > ABORT REMIRROR.
- REMIRROR PARTITION logical_partition_number
  Remirrors a designated partition to a previously mirrored set. NetWare automatically remirrors partitions when they become unsynchronized. Use REMIRROR PARTITION only if something has caused the server to stop remirroring. See Reference > Utilities Reference > Utilities > REMIRROR PARTITION.
NOTE: The status on the Mirrored Disk Partitions list is now Out of Sync for one of the disks. As soon as mirroring is complete, the status of both disks changes to In Sync.

Status	Explanation
Mirrored	The partition is mirrored to another partition.
Not Mirrored	The partition is not mirrored to another partition.
Out of Sync	The partition is mirrored to another partition, but is currently out of sync.

Unmirroring Partitions

You must unmirror mirrored partitions before you can delete a partition or conduct surface tests on a disk.

WARNING: If you plan to replace a mirrored Hot Plug disk while the system is running, you must first unmirror the partitions on the disk.

At the server console prompt, enter
[LOAD] NWCONFIG
Select Standard Disk Options > Mirror/Unmirror Disk Partitions.

The system displays the Disk Partition Mirroring Status list.
Select a mirrored partition from the list.

After you select a partition, the system displays the list of disk partitions in the mirrored set.
Select the partition you want to unmirror from the set and press Delete.

If volumes were not dismounted from the partition, the system displays a message warning that the partition contains volume information.
Press Enter to clear the message.

A confirmation prompt is displayed. You have the option to save the information on the partition or delete it.
Choose Yes to salvage the information on the partition or No if you do not want to salvage the data.
- If you choose No, the data is destroyed and the Mirrored Disk Partitions list is redisplayed.
- If you choose Yes, the system warns that the selected partition contains a volume with a name and segment number matching an existing volume. Continue with Steps 7a and 7b.
1. Press Enter to clear the message.
  
  The system prompts you to enter a new name for the volume.
2. Enter the new volume name.
  
  The Mirrored Disk Partitions list is redisplayed.
Press Esc from the Mirrored Disk Partitions list.

The Disk Partition Mirroring Status list is displayed. The Out of Sync status appears next to the disk you unmirrored.

You can now
- Allocate the unmirrored partition as a new volume segment, if you did not salvage the data on the partition. See Contents > Traditional File Services > Managing > Managing Volumes > Changing Volume Size for instructions on creating the new volume segment.

Recovering Data from an Out of Sync Disk

Once a hard disk is unmirrored, its status is listed as either Not Mirrored or Out of Sync on the Disk Partition Mirroring Status list.

When a hard disk is listed as Out of Sync, the operating system does not recognize any volume information on it. Use this procedure to recover data from an Out of Sync partition.

At the server console prompt, enter
[LOAD] NWCONFIG
Select Standard Disk Options > Mirror/Unmirror Disk Partitions.
Select the Out of Sync partition and press F3.

The following warning appears if another volume segment with the same name exists on another disk:
Warning! The selected partition contains volume < name> segment < number> and that volume is already defined.
<Press ESCAPE To Continue>
1. Press Esc and respond Yes to the Rename the Volume Segment? prompt.
2. Enter a unique name for the new volume segment.
Respond Yes to the prompt to salvage the volume segment.

Now the segment can be mounted as an independent volume.