NEC Express5800/ftServer Administrator's Manual page 69

To verify that the spare disk is not in use
Type the following commands and check the resulting output:
# mdadm --detail --scan
# swapon -s
# cat /etc/mtab
To zero the spare disk
Perform one of the following procedures:
Zero the spare disk's RAID superblocks by typing a command such as the following
for each partition on the spare disk (substitute the device node of the partition you
wish to zero for sdb1 in this example):
# mdadm --zero-superblock /dev/sdb1
N O T E
Zeroing the disk's RAID superblocks takes very little time
but may not remove everything from the disk. If you are
concerned about this, zero the entire disk as described in
the following step.
Zero the entire spare disk by typing a command such as the following (substitute
the device node of the disk you wish to zero for sdf in this example).
# dd if=/dev/zero of=/dev/sdf bs=1024k
N O T E
Zeroing the entire disk takes quite a long time but
removes everything from the disk, thus eliminating many
problems.
To partition the spare disk to match the running disk
1. Save the partition table of the running disk to a file with a command like the
following:
# sfdisk -d /dev/sda > sda_partition_table
2. Write the saved partition table to the spare disk with a command like the following:
# sfdisk /dev/sdd < sda_partition_table
Administering RAID Arrays
Setting Up the ftServer System 5-21