Hot-adding a DS14, DS14mk2 FC, or DS14mk2 AT to an existing loop

About this section

This section provides information about how to hot-add a DS14, DS14mk2 FC, or DS14mk2 AT disk shelf to an existing loop. It also tabulates the error messages that appear on your storage system console if the attempt at hot-adding was unsuccessful.

Note
The hot-added disk shelf must have new drives that will be used as spares only.

Requirements for hot-adding

To hot-add a DS14, DS14mk2 FC, or DS14mk2 AT to an existing loop, the following requirements must be met.

If the disk shelf being hot-added...	Then...
Has LRC modules	The disk shelves in the existing loop must have a DS14, DS14mk2 FC, or DS14mk2 AT disk shelf with LRCs as the last shelf. You must follow the procedure Hot-adding a disk shelf to an existing loop exactly, if you are hot-adding to a mixed-shelf loop. Attention Failure to follow the procedure exactly causes the last FC9 in the loop to automatically terminate the loop. The storage system loses contact with the existing last DS14, DS14mk2 FC, or DS14mk2 AT in the loop and crashes.
Has ESH or ESH2 modules	The disk shelves in the existing loop must have only DS14, DS14mk2 FC, or DS14mk2 AT disk shelves with ESH or ESH2 modules in the loop.
Has AT-FCX modules	The disk shelves in the existing loop must have only DS14mk2 AT disk shelves with AT-FCX modules in the loop.

Hot-adding a disk shelf to an existing loop

To hot-add a disk shelf to an existing loop, complete the following steps.

Step	Action
1	Put on the antistatic wrist strap and grounding leash.
2	Install the disk shelf. See the DiskShelf14, DiskShelf14mk2 FC, or DiskShelf14mk2 AT Hardware Guide for more information.
3	Ground the disk shelf using the provided grounding cable. See the DiskShelf14, DiskShelf14mk2 FC, or DiskShelf14mk2 AT Hardware Guide for more information.
4	Connect the disk shelf to a power source. See the DiskShelf14, DiskShelf14mk2 FC, or DiskShelf14mk2 AT Hardware Guide for more information.
5	Give the disk shelf a unique disk shelf ID. See the DiskShelf14, DiskShelf14mk2 FC, or DiskShelf14mk2 AT Hardware Guide for more information. Note Only use disk shelf ID 1 through 6. Disk shelf ID 7 is reserved for other purposes.
6	Verify that the disk shelf ID is not being used in the loop by entering the following command at the console: fcstat device_map adaptername Attention An invalid disk shelf ID causes the storage system to panic.
7	If disk shelves in the loop have...	Then, for loops with...
	LRC modules	DS14 only: Go to Step 8. A mix of DS14 and DS14mk2 FC: Set the loop speed to 1 Gb. Attention An incorrectly set loop speed results in an open loop condition.
	ESH, ESH2, or AT-FCX modules	DS14 only or a mix of DS14 and DS14mk2 FC: Set the loop speed to 1 Gb. DS14mk2 FC only that are running at 1 Gb: Set the loop speed to 1 Gb. DS14mk2 FC only that are running at 2 Gb: Set the loop speed to 2 Gb. Attention An incorrectly set loop speed causes the storage system to panic. DS14mk2 AT: Loop speed is fixed and automatically set at 2 Gb.
8	If the disk shelf you added has...	Then...
	ESH2 modules	Turn on the power to the disk shelf and wait 60 seconds for the electronics to finish initializing.
	LRC or ESH modules	Turn on the power to the disk shelf and wait 60 seconds for the electronics to finish initializing. Attention You must power up the new disk shelf before you connect it to the last disk shelf in the loop because there must be approximately a 60-second time difference between Step 8 (powering on the disk shelf) and Step 14 (turning off the terminate switch) of this procedure.
	AT-FCX modules	Turn on the power to the disk shelf and wait 60 seconds for the electronics to finish initializing. Note The AT-FCX module is self terminating as long as no cable is plugged into the Out port of the last shelf.
9	Connect one end of the provided cable to the LRC, ESH, ESH2, or AT-FCX Channel A Input on the new disk shelf.
10	Connect the other end of the cable to the LRC, ESH, ESH2, or AT-FCX Channel A Output on the last disk shelf in the existing loop.
11	Connect one end of the provided cable to the LRC, ESH, ESH2, or AT-FCX Channel B Input on the new disk shelf.
12	Connect the other end of the cable to the LRC, ESH, ESH2, or AT-FCX Channel B Output on the last disk shelf in the existing loop.
13	Verify that all the cables are securely fastened. Attention Poorly secured cables cause the storage system to panic over an open loop.
14	If the disk shelf you added has...	Then...
	ESH2 or AT-FCX modules	Result In 60 seconds, the storage system recognizes the hot-added disk shelf.
	LRC or ESH modules	Turn the terminate switch of the newly added disk shelf to the On position for LRC or ESH Channel A (down) and LRC or ESH Channel B (up). Attention Failure to place the terminate switches in the On position causes the storage system to panic over an open loop. Turn the terminate switch of the now second-to-last disk shelf to the Off position for LRC or ESH Channel A (up) and LRC or ESH Channel B (down). Result In 60 seconds, the storage system recognizes the hot-added disk shelf.

Error messages

The following error messages appear on your storage system console if your attempt at hot-adding the DS14/DS14mk2 FC is unsuccessful.

Error message	Explanation
Open loop panic	One of three reasons cause this error message to appear: The terminate switch on LRC or ESH Channel A and LRC or ESH Channel B on the new disk shelf are not in the On position. The shelf-to-shelf cable between the now second-to-last disk shelf and the newly added disk shelf is defective or is not securely fastened. The speed of the newly added DS14mk2 FC disk shelf is incorrectly set.
Soft address panic	One of two reasons cause this error message to appear: There is an invalid disk shelf ID. The power was turned on before the disk shelf ID was changed and the disk shelf was not power-cycled after the disk shelf ID was changed.
Speed mismatch termination	The ESH modules on the disk shelf detected a speed mismatch between the preceding disk shelf and this disk shelf and is reporting them as automatic termination errors.

Error message

Explanation

Open loop panic

One of three reasons cause this error message to appear:

The terminate switch on LRC or ESH Channel A and LRC or ESH Channel B on the new disk shelf are not in the On position.
The shelf-to-shelf cable between the now second-to-last disk shelf and the newly added disk shelf is defective or is not securely fastened.
The speed of the newly added DS14mk2 FC disk shelf is incorrectly set.

Soft address 
panic

One of two reasons cause this error message to appear:

There is an invalid disk shelf ID.
The power was turned on before the disk shelf ID was changed and the disk shelf was not power-cycled after the disk shelf ID was changed.

Speed mismatch 
termination

The ESH modules on the disk shelf detected a speed mismatch between the preceding disk shelf and this disk shelf and is reporting them as automatic termination errors.