4.3 The RECONSTRUCT Command
Table 4–1 Bank Configurations
Configuration
Explanation
Case 1
DSBL = 0 and SUBS = 0
Reconstruction is invalid in this configuration.
Case 2
DSBL = nonzero, and
SUBS = 0
The drive identified by DSBL is the
RECONSTRUCT target. Upon successful
reconstruction, DSBL is automatically set to 0.
Case 3
DSBL = nonzero, SUBS
= nonzero, and DSBL =
SUBS
The drive identified by DSBL/SUBS is reconstructed
onto the standby drive. Upon successful
reconstruction, DSBL is automatically set to 0,
and SUBS is left unchanged.
Case 4
DSBL = nonzero, SUBS
= nonzero, DSBL
SUBS
This is the same as Case 2, except one other drive
is already assigned as standby.
•
target = 0: The drive identified by DSBL is
the RECONSTRUCT target. Upon successful
reconstruction, DSBL is automatically set to 0.
•
target = 1: The drive identified by SUBS is
the RECONSTRUCT target. Upon successful
reconstruction, SUBS is automatically set to 0
(deassigning the standby drive).
Case 5
DSBL = 0, SUBS =
nonzero
The drive identified by SUBS is the
RECONSTRUCT target. Upon successful
reconstruction, SUBS is automatically set to 0
(deassigning the standby drive).
When a drive is deemed inoperable, use the
dadsbl(8)
command to load the
DSBL field of the appropriate Bank Configuration Table with the inoperable drive
number. All subsequent read operations on the bank use the parity replacement
drive to provide correct data to the host, and all write operations avoid the
disabled drive.
You now have two options:
• If no standby drive is available, physically replace the inoperable drive with a
new drive:
1. Format (using the
daformat(8)
command) the new drive.
2. Reconstruct (using the
darecon(8)
command) the original drive’s data.
When RECONSTRUCT completes without error, the DA controller
automatically clears the DSBL field. This action falls under Case 2 in
Table 4–1.
• If a standby drive is available, you can assign it to replace the inoperable
drive:
1. Use the
dasubs(8)
command to set the SUBS field equal to the DSBL
field of the Bank Configuration Table.
2. Enter the
darecon(8)
command to reconstruct the data.
When RECONSTRUCT completes without errors, the controller automatically
clears the DSBL field. This action falls under Case 3 in Table 4–1.
Disk Formatting 4–7
