RAID5 Metadevice Status (Command Line) (Solstice DiskSuite 4.2.1 User's Guide)

Solstice DiskSuite 4.2.1 User's Guide

RAID5 Metadevice Status (Command Line)

Running the metastat(1M) command on a RAID5 metadevice shows the status of the metadevice. Additionally, for each slice in the RAID5 metadevice, metastat shows the "Device" (device name of the slice in the stripe); "Start Block" on which the slice begins; "Dbase" to show if the slice contains a state database replica; "State" of the slice; and "Hot Spare" to show the slice being used to hot spare a failed slice.

Here is sample RAID5 metadevice output from metastat.

# metastat
d10: RAID
    State: Okay        
    Interlace: 32 blocks
    Size: 10080 blocks
Original device:
    Size: 10496 blocks
        Device              Start Block  Dbase State        Hot Spare
        c0t0d0s1                 330     No    Okay        
        c1t2d0s1                 330     No    Okay        
        c2t3d0s1                 330     No    Okay

Table 3-10 explains RAID5 metadevice states.

Table 3-10 RAID5 States (Command Line)


State	Meaning
Initializing	Slices are in the process of having all disk blocks zeroed. This is necessary due to the nature of RAID5 metadevices with respect to data and parity interlace striping. Once the state changes to the "Okay," the initialization process is complete and you are able to open the device. Up to this point, applications receive error messages.
Okay	The device is ready for use and is currently free from errors.
Maintenance	A single slice has been marked as errored due to I/O or open errors encountered during a read or write operation.

The slice state is perhaps the most important information when troubleshooting RAID5 metadevice errors. The RAID5 state only provides general status information, such as "Okay" or "Needs Maintenance." If the RAID5 reports a "Needs Maintenance" state, refer to the slice state. You take a different recovery action if the slice is in the "Maintenance" or "Last Erred" state. If you only have a slice in the "Maintenance" state, it can be repaired without loss of data. If you have a slice in the "Maintenance" state and a slice in the "Last Erred" state, data has probably been corrupted. You must fix the slice in the "Maintenance" state first then the "Last Erred" slice. Refer to "Overview of Replacing and Enabling Slices in Mirrors and RAID5 Metadevices".

Table 3-11 explains the slice states for a RAID5 metadevice and possible actions to take.

Table 3-11 RAID5 Slice States (Command Line)


State	Meaning	Action
Initializing	Slices are in the process of having all disk blocks zeroed. This is necessary due to the nature of RAID5 metadevices with respect to data and parity interlace striping.	Normally none. If an I/O error occurs during this process, the device goes into the "Maintenance" state. If the initialization fails, the metadevice is in the "Initialization Failed" state and the slice is in the "Maintenance" state. If this happens, clear the metadevice and recreate it.
Okay	The device is ready for use and is currently free from errors.	None. Slices may be added or replaced, if necessary.
Resyncing	The slice is actively being resynced. An error has occurred and been corrected, a slice has been enabled, or a slice has been added.	If desired, monitor the RAID5 metadevice status until the resync is done.
Maintenance	A single slice has been marked as errored due to I/O or open errors encountered during a read or write operation.	Enable or replace the errored slice. See "How to Enable a Slice in a RAID5 Metadevice (Command Line)", or "How to Replace a RAID5 Slice (Command Line)". Note: The `metastat(1M)` command will show an `invoke` recovery message with the appropriate action to take with the `metareplace(1M)` command.
Maintenance/ Last Erred	Multiple slices have encountered errors. The state of the errored slices is either "Maintenance" or "Last Erred." In this state, no I/O is attempted on the slice that is in the "Maintenance" state, but I/O is attempted to the slice marked "Last Erred" with the outcome being the overall status of the I/O request.	Enable or replace the errored slices. See "How to Enable a Slice in a RAID5 Metadevice (Command Line)", or "How to Replace a RAID5 Slice (Command Line)". Note: The `metastat(1M)` command will show an `invoke` recovery message with the appropriate action to take with the `metareplace(1M)` command, which must be run with the `-f` flag. This indicates that data might be fabricated due to multiple errored slices.