Chapter 10. Administration - Physical Tab

10.1 Physical tab

The Physical tab (Figure 10-1) shows the organization of the storage subsystem by

controllers, disk drives, and other hardware components. This tab is divided into two panes:

the Physical pane on the left and the Properties pane on the right.



Figure 10-1 The Physical tab



The Physical pane shows a graphical representation of the physical components in the

storage subsystem such as the controller modules and the drive expansion enclosures. You

can configure hardware related parameters here.

The Properties pane displays detailed information about the component that is selected in the

Physical pane. As in Logical tab, the Properties pane shows the same information that you

can find in the storage subsystem profile.

Because there is nothing to configure in the Properties pane, we will focus on the Physical

pane in the following sections:

10.2, “Discover component properties and location” on page 259

10.3, “Set hot spare drive” on page 262

10.4, “Failed disk drive replacement” on page 266

10.5, “Set preferred loop ID” on page 268

10.6, “Set remote access” on page 270

10.7, “Set Ethernet management ports” on page 270

13.4, “Configure iSCSI Host Ports” on page 317

The other configuration options in the Physical pane are already described in previous

chapters and we will provide the references as needed.



258



IBM System Storage DS3500 Introduction and Implementation Guide



10.2 Discover component properties and location

In the left Physical pane you can see schematic layout of physical enclosures of DS3500

Storage Subsystem. In Figure 10-1 on page 258, a subsystem with DS3524 controller

enclosure for 24x 2.5 inch disk drives, and one attached EXP3512 expansion enclosure for

12x 3.5 inch disk drives are displayed. You can align this layout to the actual physical

placement in your rack as described in “Enclosure Order” on page 202.



10.2.1 Show disks type

In the upper part of the Physical pane you can see one or two buttons. The first one is for

selection of SAS disks, and the second one is for SED (Self Encrypted Disk) SAS disks.

Encrypted disks are also known as FDE (Full Disk Encryption), so the button name is Show

FDE. At the time of writing this book, only SAS drives are available for DS3500, so if you click

the Show SAS disk button, all disks are marked as in Figure 10-2.



Figure 10-2 SAS disks selection



If you click the Show FDE button, disks that were selected as SAS are marked again as you

can see in Figure 10-3.



Figure 10-3 SED disks selection



More information about disk encryption can be found in Chapter 15, “Disk Security with Full

Disk Encryption drives” on page 439.



10.2.2 View Enclosure Components

The second line in the Physical pane is a link that opens a new window with detailed

information about hardware components of specific enclosure (Figure 10-4 on page 260). If

you select the buttons on the bottom of the window, you can also locate this enclosure in rack

(blue LED diode starts to blink) or you can change the enclosure ID. Refer to “Enclosure ID”

on page 202 for more details.



Chapter 10. Administration - Physical Tab



259



Figure 10-4 Enclosure Properties



The remaining physical components in the Physical pane are disks and controllers. If you

select a disk or a controller, you will get relevant information about that disk or controller in the

Properties pane.



10.2.3 Disk Drive menu

If you right-click a disk drive, the menu for other configuration options appears. Certain items

in menu (Figure 10-5) might not be available because not all options are possible for all disk

drive types. This also depends on status of disk drive and how the disk is configured.



Figure 10-5 Disk drive menu



The two menu options we describe in separate sections in this chapter are:

Hot Spare Coverage in 10.3, “Set hot spare drive” on page 262

Replace Drive in 10.4, “Failed disk drive replacement” on page 266

The other menu items will be covered in the following sections.



View Associated Logical Element

If you select this menu item, you can see related logical objects as shown in Figure 10-6 on

page 261 such as arrays and logical drives that are using the selected disk drive.

260



IBM System Storage DS3500 Introduction and Implementation Guide



Figure 10-6 Associated Logical Elements



Create Array and Create Logical Drive (manual mode)

These two menu options take you to a window for creating an array or a logical drive in

manual mode. You can further select multiple unconfigured disk drives in the Physical pane

using the Ctrl key before selecting this option. If you right-click one of selected disks, and

select the Create Array menu item, the same initiation window will open as shown in

Figure 9-6 on page 224. In this window you can see, manual mode is preselected. Follow the

instructions described in 9.2.2, “Create array” on page 223, and when you reach the window

for disk drives selection, you will recognize your planned disks are already selected for the

new array.

The Create Logical Drive menu option must start with creating an array. When a new array is

created as described above, you can define a new logical drive using the same procedure as

described in Chapter 9, “Administration - Logical Tab” on page 219.



Locate

This menu item is used to find where the selected disk is placed in your enclosure in the rack.

You also have a choice to locate the enclosure where the disk is placed.



Secure Erase and Import Security File Key

If the selected disk drive in Physical pane is a SED (Self Encrypted Disk) disk drive, you will

have a choice to securely erase an unconfigured SED disk drive, or if you just inserted SED

disks from a different DS3500 Storage Subsystem, you can import a security key to enable

their use in your subsystem. For more information, refer to Chapter 15, “Disk Security with

Full Disk Encryption drives” on page 439.



10.2.4 Controller menu

If you right-click one of the two controllers in the Physical pane, the menu (Figure 10-7 on

page 262) for other controller configuration options appears.



Chapter 10. Administration - Physical Tab



261



Figure 10-7 Controller menu



View Associated Logical Element

If you select this menu item, you can see a list of related logical objects, like array and logical

drives, that are using the selected controller.



Locate

This is used to find location of the selected controller in your enclosure in the rack.



Change

Select this menu item and configuration options that are displayed include:

Preferred Loop ID: This is discussed in detail in 10.5, “Set preferred loop ID” on page 268

(FC version only).

Remote Login: This is discussed in detail in 10.6, “Set remote access” on page 270



Configure

Select this menu item and configuration options that are displayed include:

Ethernet Management Ports: This is discussed in detail in 10.7, “Set Ethernet

management ports” on page 270

iSCSI Ports: This is discussed in detail in Chapter 13, “Administration - iSCSI” on

page 309, and this menu is available only if subsystem has iSCSI daughter card installed.



10.3 Set hot spare drive

A hot spare drive is like a replacement disk drive installed in advance. Hot spare disk drives

provide additional protection that can be essential if there is a disk drive failure in a

fault-tolerant RAID array.

As DS3500 Storage Subsystem configuration can only have SAS disk types, but with different

capacities and speeds, you have to plan in advance how to provide the best hot spare

protection for your storage subsystem.

Follow these guidelines to plan your hot spare coverage properly:

Hot spare disk drives must be of the same media type and interface type as the disk drives

that they are protecting.

Hot spare disk drives must have capacities equal to or larger than the used capacity on the

disk drives that they are protecting. The DS3500 storage subsystem can use a larger drive

to recover a smaller failed drive to. It cannot use smaller drives to recover a larger failed

drive. If a larger drive is used, the remaining excess capacity is blocked from use.

FDE (SED) disk drives (encryptable) provide coverage for both security capable and

non-security capable disk drives. Non-security capable disk drives can provide coverage

only for other non-security capable disk drives.

– For an array that has secured FDE drives (security key activated), the hot-spare drive

should be a secured or unsecured FDE drive only, with the same or greater capacity.

262



IBM System Storage DS3500 Introduction and Implementation Guide



– For an array that has FDE drives that are not secured (security key not activated yet),

the hot-spare drive can be either a FDE drive or a non-FDE drive.

In a mixed disk environment that includes NearLine SAS drives, high speed SAS drives, and

FDE (SED) SAS drives (either with security enabled or not enabled), use at least one disk

drive of each type at the largest capacity within the array.

Important: When assigning disks as hot spares, make sure they have enough storage

capacity. If the failed disk’s used capacity is larger than the hot spare capacity,

reconstruction is not possible. Ensure that you have at least one of each size or all larger

drives configured as hot spares.



Hot spares locations

Distribute the hot spare drives evenly across the expansions of your storage subsystem, but

avoid having multiple ones in a single enclosure. Because hot spare drives are in standby,

without traffic or I/O until a drive fails, you want to maximize the overall performance of your

system by evenly distributing your production drives across the different expansions. At the

same time, this avoids the risk of a single disk drive channel, or expansion enclosure failure

causing loss of access to all hot spare drives in the storage subsystem.



Quantity and type of hot-spares drives

There is no fixed rule about the quantity of disk drives to assign as hot spares, but as a

general rule, define at least one of every 18 - 20 disk drives of a particular media type and

interface type, or one for every two fully populated enclosures. Because of disk sizes, and

especially in large configurations with arrays containing numerous drives, the reconstruction

of a failed drive to a hot spare drive can take a long time proportional to the quantity of drives

in the array and the size of the disks. If in addition to that time, you have to wait to have a new

disk available on-site to replace the failed drive, then the probability of having another disk

failure increases. Having multiple spare drives will not mitigate the reconstruction time, but at

least an array will be prepared sooner for a second disk failure.

Note: There is no definitive rule about how many hot spares you should install, but use a

ratio of one hot spare for about 18 - 20 identical disk drives in large installations. In small

installations with just a couple of disks in DS3500 Controller enclosure, use one hot spare

disk of largest capacity for high speed SAS and one for NearLine SAS, if both these types

are used.

In the following section we cover the available methods of defining hot spare drives with

Storage Manager.

To start the configuration of a new hot spares from the Physical pane, select an unconfigured

disk drive that you plan to use as hot spare disk, right-click it, and select Hot Spare

Coverage. The window shown in Figure 10-8 on page 264 opens.



Chapter 10. Administration - Physical Tab



263



Figure 10-8 Hot Spare Drive options



You have four options to define hot spare drives:

View/Change coverage

Automatic assignment

Manual assignment (if unassigned disk was selected in the Physical pane)

Manual unassignment (if hot spare disk was selected in the Physical pane)



Automatic assignment

For automatic hot spare assignment, follow these steps:

1. To automatically create the hot spare coverage using the drives that are available, select

Automatically assign drives. The recommended quantity of spares drives needed for

your configuration are created automatically.

2. Select the Physical tab to view the results of the automatic hot spare creation.

This automatic hot spare creation function on DS3500 creates one hot spare drive for every

10 unassigned disk drives. Results can be unexpected in environment with mixed drive types

and if disk drives are already assigned to arrays. In such scenarios, we recommend using the

manual assignment, instead of the automatic method.



Manual assignment and unassignment

To perform manual hot spare assignment, follow these steps:

Select an unconfigured disk drive that you plan to use as hotspare disk, right-click it, and

select Hot Spare Coverage. The window shown in Figure 10-8 displays with the option

Manually assign individual drives already preselected. Click OK and the unassigned

drive is defined as a hot spare.

Select a hot spare disk drive that you plan not to use as hotspare disk any more, right-click

it, and select Hot Spare Coverage. The window shown in Figure 10-8 display with the

option Manually unassign individual drives already preselected. Click OK, confirm by

typing yes in next window, and the former hot spare drive is an unassigned disk drive

again.



264



IBM System Storage DS3500 Introduction and Implementation Guide



Tip for hot spare selection:

Select drives of equal or greater size than the capacity of the largest disk in the storage

subsystem.

In large configurations with arrays containing many drives, it is necessary to define

multiple hot spares as the reconstruction of a failed drive to a hot spare can take a long

time.

Consider having hot spares for each speed and type of disk drives, that is SAS,

NearLine SAS, and SED SAS (encryptable).



View/change hot spare coverage

In the Hot Spare Drive Option window (Figure 10-8 on page 264) select the View/change hot

spare coverage option. The Hot Spare Coverage window similar to Figure 10-9 appears.



Protected



Figure 10-9 View/Change hot spare coverage



This window has four panes:

The Summary pane, which displays:

– Numbers of hot spares

– Number of hot spares in use

– Number of unassigned disks that can be used as hot spares

The Hot spare coverage pane shows all arrays and whether they are protected by hot

spares. If an array is selected in this left pane, in the right Hot spare drives pane you see

the hot spare assigned. If you select an array that has no hot spare defined, you can click

Assign in the bottom part of the window, and a new window like in Figure 10-10 on

page 266 opens.



Chapter 10. Administration - Physical Tab



265



Figure 10-10 Assigning hot spare



Here you can select new hot spare for your unprotected array.

The Hot spare drives pane shows hot spare drives used. If you have more hot spare drives

then you need, you can select hot spare drive here, and click Unassign to unassign it. The

Unassign button will be unavailable if you can lose protection by unassigning this hot

spare disk. If you still need to unassign this hot spare drive, do it manually as described in

“Manual assignment and unassignment” on page 264.

The Details pane shows logical objects that belong to selected array or hot spare in panes

above.

Make sure to use this window to check that all your arrays are protected. If they are not

protected, implement complete hot spare protection for all arrays as soon as possible.



10.4 Failed disk drive replacement

You can replace a failed or missing disk drive that is used by an array. Logical drives are in

“Degraded” status if parity for the failed disk is still calculated to the hot spare drive (see the

example of the Recovery Guru window in Figure 10-11 on page 267).

You can assign a working unassigned disk drive that is already inserted in the DS3500

Storage Subsystem as a replacement drive. In addition, the hot spare in use can be used as

replacement drive but only after parity recalculation is completed.



266



IBM System Storage DS3500 Introduction and Implementation Guide



Figure 10-11 Degraded Logical Drive + Hot Spare In Use



To replace a failed disk drive, perform the following steps:

1. Select the failed disk drive or missing disk drive icon in the Physical pane, right-click it, and

select Replace Drives in the menu that appears (Figure 10-12).



Figure 10-12 Replace Drive



2. The list of eligible replacement disk drives appears in the window (Figure 10-13 on

page 268).



Chapter 10. Administration - Physical Tab



267



Figure 10-13 Replace Drives - Select disk



3. Select the missing or failed drive from the upper list (if more than one drive is missing or

failed). Select the appropriate replacement drive from the lower list of available drives. The

available replacement disk drives are equal to or greater in size, and have the disk drive

type as the failed or missing disk drive. Select the drive that has the same or higher RPM

speed, and that has a Yes entry in the column “Enclosure Loss Protection”, if such a disk

exists in the list.

You also have a choice to select the In-Use Hot Spare drive as a replacement drive (see

Figure 10-13). If this hot spare disk drive is defined and is in use by the array with a

missing or failed disk, you have to wait until the DS3500 controller reconstructs parity of all

the logical drives in that array.

4. Click the Replace Drive button to start the operation. The confirmation window appears.

Click OK and a new updated window like Figure 10-13 shows any remaining missed or

failed drives to replace. Continue with the replacement or click Close to finish.



Warning: Because of possible loss of data access, use the Replace Drives option to

logically change disk drives only. Physical removal and replacement of a failed disk drive

might damage the array and the data on the drive, and the data might not be recovered.

If an In-Use Hot Spare disk drive is used as replacement drive, define another disk drive as

a hot spare. Returning a missing disk or repaired disk does not set the Hot Spare setting

automatically. A repaired or reinserted disk drive becomes a regular unassigned disk drive.



10.5 Set preferred loop ID

Loop ID is unique ID of a port in fibre-channel loop topology, sometimes is referred as a loop

address. The Preferred Loop ID menu is not available for DS3500 without a FC daughter

card installed.

268



IBM System Storage DS3500 Introduction and Implementation Guide