Avago Technologies MegaRAID Fast Path Software - Manual (Page 403)

LSI Corporation Confidential | July 2011 Page 403
MegaRAID SAS Software User Guide Chapter 10: Maintaining and Managing Storage Configurations | Scanning for New Drives
10.3 Scanning for New Drives You can use the Scan for Foreign Configuration option to find drives with foreign
configurations. A foreign configuration is a RAID configuration that already exists on a
replacement set of physical disks that you install in a computer system. In addition, if
one or more drives are removed from a configuration, by a cable pull or drive removal,
for example, the configuration on those drives is considered a foreign configuration by
the RAID controller. Drives that are foreign are listed on the physical drives list with a
special symbol in the MegaRAID Storage Manager software.
The utility allows you to import the existing configuration to the RAID controller or clear
the configuration so you can create a new configuration using these drives. You can
preview the foreign configuration before you decide whether to import it.
The MegaRAID Storage Manager software usually detects newly installed drives and
displays icons for them in the MegaRAID Storage Manager window. If for some reason
the MegaRAID Storage Manager software does not detect a new drive (or drives), you
can use the Scan for Foreign Configuration command to find it.
Follow these steps to scan for a foreign configuration:
1. Select a controller icon in the left panel of the MegaRAID Storage Manager window.
2. Select Go To >> Controller >> Scan for Foreign Configuration.
If the MegaRAID Storage Manager software detects any new drives, it displays a list
of them on the window. If not, it notifies you that no foreign configuration is found.
3. Follow the instructions on the window to complete the drive detection.
10.4 Rebuilding a Drive If a drive in a redundant virtual drive (RAID 1, 5, 6, 10, 50, or 60) fails, the MegaRAID
Storage Manager software automatically rebuilds the data on a hot spare drive to
prevent data loss. The rebuild is a fully automatic process, so it is not necessary to issue a
Rebuild command. You can monitor the progress of drive rebuilds in the Group Show
Progress window. To open this window, select Group Operations->Show Progress.
If a single drive in a RAID 1, RAID 5, RAID 10, or RAID 50 virtual drive fails, the system is
protected from data loss. A RAID 6 virtual drive can survive two failed drives. A RAID 60
virtual drive can survive two failed drives in each span in the drive group. Data loss is
prevented by using parity data in RAID 5, RAID 6, RAID 50, and RAID 60, and data
redundancy in RAID 1 and RAID 10.
The failed drive must be replaced, and the data on the drive must be rebuilt on a new
drive to restore the system to fault tolerance. You can choose to rebuild the data on the
failed rive if the drive is still operational. If dedicated hot spares or global hot spare
disks are available, the failed drive is rebuilt automatically without any user
intervention.
A red circle to the right of the drive icon indicates that a drive has failed. A
yellow circle appears to the right of the icon of the virtual drive that uses this drive
which indicates that the virtual drive is in a degraded state; the data is still safe, but data
could be lost if another drive fails.