Dell PowerEdge T40 EMC PowerEdge Servers Troubleshooting Guide - Page 62

Rebuilding the physical disks after multiple disks become simultaneously inaccessible

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Table 17. Estimated rebuild rates RAID level Number of Hard Drives RAID 1 2 RAID 5 6 RAID 10 6 RAID 5 24 RAID 10 24 7.2 K rpm 12 Gbps SAS Hard Drive 320 GB/hour 310 GB/hour 320 GB/hour 160 GB/hour 380 GB/hour 15 K rpm 6 Gbps SAS Hard Drive 500 GB/hour 480 GB/hour 500 GB/hour 240 GB/hour 500 GB/hour Rebuilding the physical disks after multiple disks become simultaneously inaccessible About this task Multiple physical disk errors in a single array typically indicate a failure in cabling or connection and could involve the loss of data. You can recover the virtual disk after multiple physical disks become simultaneously inaccessible. Perform the following steps to recover the virtual disk: Steps 1. Turn off the system, check cable connections, and reseat physical disks. 2. Ensure that all the drives are present in the enclosure. 3. Turn on the system and enter the CTRL+R utility and import the foreign configuration. Press at the prompt to import the configuration, or press to enter the BIOS configuration utility and either import or clear the foreign configuration. 4. If the virtual disk is redundant and transitioned to Degraded state before going Offline, a rebuild operation starts automatically after the configuration is imported. 5. If the virtual disk has gone directly to the Offline state due to a cable pull or power loss situation, the virtual disk is imported in its Optimal state without a rebuild occurring. 6. You can use the BIOS Configuration Utility or Dell OpenManage storage management application to perform a manual rebuild of multiple physical disks. Importing a foreign configuration using PERC About this task Some controllers enable you to import a foreign configuration so that virtual disks are not lost after moving the physical disks. You can import a foreign configuration only if it contains a virtual disk that is either in a Ready or Degraded state. In other words, all of the virtual disk data must be present, but if the virtual disk is using a redundant RAID level, the additional redundant data is not required. For example, if the foreign configuration contains only one side of a mirror in a RAID 1 virtual disk, then the virtual disk is in a Degraded state and can be imported. On the other hand, if the foreign configuration contains only one physical disk that was originally configured as a RAID 5 using three physical disks, then the RAID 5 virtual disk is in a Failed state and cannot be imported. In addition to virtual disks, a foreign configuration may consist of a physical disk that was assigned as a hot spare on one controller and then moved to another controller. The Import Foreign Configuration task imports the new physical disk as a hot spare. If the physical disk was set as a dedicated hot spare on the previous controller, but the virtual disk to which the hot spare was assigned is no longer present in the foreign configuration, then the physical disk is imported as a global hot spare. The Import Foreign Configuration task is only displayed when the controller has detected a foreign configuration. You can also identify whether a physical disk contains a foreign configuration (virtual disk or hot spare) by checking the physical disk state. If the physical disk state is Foreign, then the physical disk contains all or some portion of a virtual disk or has a hot spare assignment. If you have an incomplete foreign configuration which cannot be imported, you can use the Clearing Foreign Configuration option to erase the foreign data on the physical disks. NOTE: The task of importing foreign configuration imports all virtual disks residing on physical disks that have been added to the controller. If more than one foreign virtual disk is present, all the configurations are imported. When a foreign configuration exists, the BIOS screen displays the message Foreign configuration(s) found on adapter. In addition, a foreign configuration is displayed on the right side of the Ctrl Mgmt screen. To import or clear a foreign configuration, do the following: Steps 1. During bootup, press Ctrl + R when prompted by the BIOS screen. The VD Mgmt screen is displayed by default. 62 Troubleshooting hardware issues

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Table 17. Estimated rebuild rates
RAID level
Number of Hard Drives
7.2 K rpm 12 Gbps SAS Hard
Drive
15 K rpm 6 Gbps SAS Hard
Drive
RAID 1
2
320 GB/hour
500 GB/hour
RAID 5
6
310 GB/hour
480 GB/hour
RAID 10
6
320 GB/hour
500 GB/hour
RAID 5
24
160 GB/hour
240 GB/hour
RAID 10
24
380 GB/hour
500 GB/hour
Rebuilding the physical disks after multiple disks become simultaneously inaccessible
About this task
Multiple physical disk errors in a single array typically indicate a failure in cabling or connection and could involve the loss of data. You can
recover the virtual disk after multiple physical disks become simultaneously inaccessible.
Perform the following steps to recover the virtual disk:
Steps
1.
Turn off the system, check cable connections, and reseat physical disks.
2.
Ensure that all the drives are present in the enclosure.
3.
Turn on the system and enter the
CTRL+R
utility and import the foreign configuration. Press
<"F">
at the prompt to import the
configuration, or press
<"C">
to enter the BIOS configuration utility and either import or clear the foreign configuration.
4.
If the virtual disk is redundant and transitioned to Degraded state before going Offline, a rebuild operation starts automatically after
the configuration is imported.
5.
If the virtual disk has gone directly to the Offline state due to a cable pull or power loss situation, the virtual disk is imported in its
Optimal state without a rebuild occurring.
6.
You can use the BIOS Configuration Utility or Dell OpenManage storage management application to perform a manual rebuild of
multiple physical disks.
Importing a foreign configuration using PERC
About this task
Some controllers enable you to import a foreign configuration so that virtual disks are not lost after moving the physical disks. You can
import a foreign configuration only if it contains a virtual disk that is either in a
Ready
or
Degraded
state. In other words, all of the virtual
disk data must be present, but if the virtual disk is using a redundant RAID level, the additional redundant data is not required. For example,
if the foreign configuration contains only one side of a mirror in a RAID 1 virtual disk, then the virtual disk is in a
Degraded
state and can be
imported. On the other hand, if the foreign configuration contains only one physical disk that was originally configured as a RAID 5 using
three physical disks, then the RAID 5 virtual disk is in a
Failed
state and cannot be imported. In addition to virtual disks, a foreign
configuration may consist of a physical disk that was assigned as a hot spare on one controller and then moved to another controller. The
Import Foreign Configuration
task imports the new physical disk as a hot spare. If the physical disk was set as a dedicated hot spare on
the previous controller, but the virtual disk to which the hot spare was assigned is no longer present in the foreign configuration, then the
physical disk is imported as a global hot spare. The
Import Foreign Configuration
task is only displayed when the controller has
detected a foreign configuration. You can also identify whether a physical disk contains a foreign configuration (virtual disk or hot spare)
by checking the physical disk state. If the physical disk state is
Foreign
, then the physical disk contains all or some portion of a virtual disk
or has a hot spare assignment. If you have an incomplete foreign configuration which cannot be imported, you can use the
Clearing
Foreign Configuration
option to erase the foreign data on the physical disks.
NOTE:
The task of importing foreign configuration imports all virtual disks residing on physical disks that have been
added to the controller. If more than one foreign virtual disk is present, all the configurations are imported.
When a foreign configuration exists, the BIOS screen displays the message
Foreign configuration(s) found on adapter
. In addition, a
foreign configuration is displayed on the right side of the
Ctrl Mgmt
screen. To import or clear a foreign configuration, do the following:
Steps
1.
During bootup, press Ctrl + R when prompted by the BIOS screen.
The
VD Mgmt
screen is displayed by default.
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Troubleshooting hardware issues