SDA States and Types (93-191r1)
George Penokie
GOP at rchvmp3.vnet.ibm.com
Tue Jan 4 15:24:30 PST 1994
Date: Dec 12,1993 X3T9.2/93-191 rev 1
To: X3T9.2 Committee (SCSI)
From: George Penokie (IBM)
Subject: SDA States and Types
1.0 Overview
The SCSI-3 Disk Array Model requires the definition of several
new SCSI device types. This proposal lists all the new SCSI
devices types that are required for the SCSI-3 Disk Array
Model.
The SCSI-3 Disk Array Model also needs to define the state of
SCSI devices. The state of a device is an indication of its
current operating condition. The state information gives an
application client the information required for to do
configuration services to a SDA.
2.0 SCSI-3 Device Types
This proposal requests the following peripheral device
types be added to the SCSI-3 peripheral device type table:
+========-====================================================+
| Code | Description |
|--------+----------------------------------------------------+
| 0Ch | SCSI disk array device |
| 0Dh | Power supply device |
| 0Eh | Operation panel device |
| 0Fh | LED device |
|10h-19h | Vendor Specific |
+=============================================================+
These changes would become part of the peripheral device type
table in the SCC standard. The new peripheral device type
table would appear as follows:
| <<Editors note: There have been several requests that the power
| supply, op panel, LED, etc. not be listed as a peripheral
| device type. One suggestion was to use the Peripheral
| qualifier for those types. Another was to use the Device-type
| modifier. This needs to be thought about so more. - GOP>>
.pa
Table xx - Peripheral device type
+========-====================================================+
| Code | Description |
|--------+----------------------------------------------------+
| 00h | Direct-access device (e.g. magnetic disk) |
| 01h | Sequential-access device (e.g. magnetic tape) |
| 02h | Printer device |
| 03h | Processor device |
| 04h | Write-once device (e.g. some optical disks) |
| 05h | CD-ROM device |
| 06h | Scanner device |
| 07h | Optical memory device (e.g. some optical disks) |
| 08h | Medium changer device (e.g. jukeboxes) |
| 09h | Communications device |
|0Ah-0Bh | Defined by ASC IT8 (Graphic arts pre-press devices)|
|| 0Ch | SCSI disk array device |
|| 0Dh | Power supply device |
|| 0Eh | Operation panel device |
|| 0Fh | LED device |
|| 10h | Fan Device |
||11h-19h | Vendor Specific |
||1Ah-1Eh | Reserved |
| 1Fh | Unknown or no device type |
+=============================================================+
3.0 SCSI-3 Disk Array States
The following is a list of states that shall be returned as
part of the parameter list returned in SDA service requests.
Readying - The selected logical unit is being initialized and
access to the logical unit is limited.
| Available - The selected logical unit is fully operational.
Implementors Note: A logical unit that has a redundancy type of
no redundancy should report a state of available rather than
exposed during normal operations.
| Present - The selected logical unit is present but no other
| status is available.
Rebuild - The selected logical unit is in the process of a
rebuild operation.
Recalculate - The selected logical unit is in the process of a
recalculate operation.
Error - Within the selected logical unit a part that does not
effect performance has failed. In this state all data is
still fully protected (e.g. power supply failure, LED
failure, etc.).
Degraded Performance - Within the selected logical unit a part
that effects performance has failed. In this state all data
is still fully protected (e.g. cache failure, etc.)
Exposed - Within the selected logical unit data is not
protected. In this state all data is still valid.
Note: This is a normal state if the logical unit is within a
redundancy group that has a redundancy type of no redundancy.
| Data Lost - Within the selected logical unit data has been
lost.
Not Available - The selected logical unit is capable of being
supported but no device is connected.
Broken - The selected logical unit is capable of being
supported but it has failed.
| Not Supported - The SDA is not capable of supporting a device
| on the selected logical unit.
<<Editors note:I do not think this table has any value and would
like to remove it. Any comments? - GOP>>
P-extent P-LUI Redundancy Volume Set Spare
Group
Readying Y Y Y Y Y
Available Y Y Y Y Y
| Present
Rebuild Y Y Y Y Y
Recalculate Y Y Y Y Y
Error Y Y Y Y Y
Degraded Perf. Y Y Y Y Y
Exposed N N Y Y N
Data Lost N N Y Y N
Not Available Y Y N N N
Broken Y Y N N Y
Not Supported Y Y Y Y Y
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