Internal Support Note – Company Confidential
CLARiiON Internal Support Note
Subject: How to Clear a Cache Dirty Condition on an EMC CLARiiON Series FC5600/5700 Disk-Array and
Licensed Internal Code with Partitioning Features
Note Number: I991117
Note
This Internal Support Notes describes how to clear a "cache dirty" condition on an EMC CLARiiON
FC5600/5700 Series disk-array. Cache dirty occurs when the array was shut down and for some reason cache
data could not be saved to a vault drive. When that happens, the LUN becomes inaccessible. The unsolicited
event log (ulog) displays a message like the following:
Enclosure 0 Disk 5 0x90a (Can't Assign - Cache Dirty) 0 0xafb40 0x14362c
Navisphere Manager or Supervisor shows that the inaccessible LUN is unowned.
The procedure described below attempts to recover the LUN by clearing the cache dirty indicator for the LUN.
The procedure clears cache dirty by
• Reading configuration information from disk
• Storing the configuration information in memory
• Clearing a word of that configuration information in memory
• Writing the configuration information to disk with the cleared word
After the configuration information with the cleared word is written to disk, the LUN is accessible. However,
the customer should be informed that any data that was in cache before the LUN became inaccessible will be
lost. Furthermore, the customer should check for data integrity after this procedure is completed. The only
alternative to this procedure is unbinding and rebinding the affected LUN to make it available to the operating
system, and then reloading data onto the unit from an available backup.
Follow these steps to fix the problem:
(User input is in bold.)
1. Stop the server from accessing the array during this operation by disconnecting the fibre cable to the host
bus adapter (HBA). This ensures that no I/O is directed to the storage processor (SP) while you are
performing the operation.
2. Determine which LUN or LUNs are experiencing the cache dirty condition. Identify from the unsolicited
event log (ulog) which two disk drives in each LUN have the cache dirty condition.
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3. Determine which SP controls the LUN that has the cache dirty condition and then disable the other SP.
4. Connect a serial cable from the server or a laptop to the serial port on the SP you are going to use. The
connection parameters for a serial connection are 9600 baud, 8 bit word length, and no parity.
5. Enter the debugger by typing @$@$ (where the key sequence is shift 2, shift 4, shift 2, shift 4).
Information like the following is displayed:
Exception: System Call
SRR0 =FFF05198 SRR1 =0000B040 Vector-Offset =00C00
IP =FFF05198 MSR =0000B040 CR =40000042 FPSCR =00000000
R0 =00000018 R1 =001CCC00 R2 =9000C000 R3 =001BCC4C
R4 =001BCD7C R5 =001CCB20 R6 =001BCD88 R7 =00000000
R8 =001BEBDC R9 =001BD314 R10 =00000063 R11 =001BEBF4
R12 =001D7814 R13 =00000000 R14 =00000000 R15 =00000000
R16 =00000000 R17 =00000000 R18 =00000000 R19 =00000000
R20 =00000000 R21 =00000000 R22 =00000000 R23 =00000000
R24 =00000000 R25 =00000000 R26 =00000000 R27 =00000000
R28 =001421D4 R29 =FFF05190 R30 =001F0D11 R31 =001CCC00
SPR0 =00000000 SPR1 =00000000 SPR8 =FFF1437C SPR9 =FFF2A31C
FFF05198 60000000 ORI R0,R0,$0
AROM>
6. Enter MENU. The Diagnostic menu is displayed.
7. Select 13 ("Disk Menu") to display the Disk Menu.
8. Select 2 ("Disk Read") and enter the disk ID. The disk ID consists of the enclosure number followed by the
disk number. For example, 05 is enclosure 0, disk number 5.
9. At the "Enter # sectors" prompt, enter 1.
10. If you have one large LUN in the RAID Group at the "Enter starting sector (HEX)" number prompt, enter
3003. The following message and prompt are displayed:
Initializing Back End Fibre…
Continue? (y/n)
OR
With Partitioned Denali you can create up to 32 LUNs for each RAID Group. If the RAID Group has
multiple LUNs, at the "Enter starting sector (HEX)" number prompt enter the starting sector for the
corresponding LUN :
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lun 0 --> sector 0x3003
lun 1 --> sector 0x5B6F
lun 2 --> sector 0x5B70
lun 3 --> sector 0x5B71
lun 4 --> sector 0x5B72
lun 5 --> sector 0x5B73
lun 6 --> sector 0x5B74
lun 7 --> sector 0x5B75
lun 8 --> sector 0x5B76
lun 9 --> sector 0x5B77
lun 10 --> sector 0x5B78
lun 11 --> sector 0x5B79
lun 12 --> sector 0x5B7A
lun 13 --> sector 0x5B7B
lun 14 --> sector 0x5B7C
lun 15 --> sector 0x5B7D
lun 16 --> sector 0x5B7E
lun 17 --> sector 0x5B7F
lun 18 --> sector 0x5B80
lun 19 --> sector 0x5B81
lun 20 --> sector 0x5B82
lun 21 --> sector 0x5B83
lun 22 --> sector 0x5B84
lun 23 --> sector 0x5B85
lun 24 --> sector 0x5B86
lun 25 --> sector 0x5B87
lun 26 --> sector 0x5B88
lun 27 --> sector 0x5B89
lun 28 --> sector 0x5B8A
lun 29 --> sector 0x5B8B
lun 30 --> sector 0x5B8C
lun 31 --> sector 0x5B8D
lun 32 --> sector 0x5B8E
11. Select y and press ENTER to continue. Information like the following is displayed:
Initializing back end fibre.
1 sector successfully read to address 0x00300000
Display data now [yes]?
12. Press ENTER and data like the following will be displayed:
Sector data #nnn
-----------------------------------------------
00000000 CDCDCDCD 00000000 00000000
00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000
00000000 00000000
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Hit any key to continue, ESC to quit
13. Press ENTER to continue. The following message and prompt are displayed:
Test Complete
Hit any key to continue
14. Press ENTER to continue. The Disk Menu is displayed.
15. Enter 0 to exit and display the Diagnostic Menu.
16. Select 2 ("Enter Debugger"). Information like the following is displayed:
Exception: System Call
SRR0 =FFF05198 SRR1 =0000B040 Vector-Offset =00C00
IP =FFF05198 MSR =0000B040 CR =40000042 FPSCR =00000000
R0 =00000018 R1 =001CCC00 R2 =9000C000 R3 =001BCC4C
R4 =001BCD7C R5 =001CCB20 R6 =001BCD88 R7 =00000000
R8 =001BEBDC R9 =001BD314 R10 =00000063 R11 =001BEBF4
R12 =001D7814 R13 =00000000 R14 =00000000 R15 =00000000
R16 =00000000 R17 =00000000 R18 =00000000 R19 =00000000
R20 =00000000 R21 =00000000 R22 =00000000 R23 =00000000
R24 =00000000 R25 =00000000 R26 =00000000 R27 =00000000
R28 =001421D4 R29 =FFF05190 R30 =001F0D11 R31 =001CCC00
SPR0 =00000000 SPR1 =00000000 SPR8 =FFF1437C SPR9 =FFF2A31C
FFF05198 60000000 ORI R0,R0,$0
AROM>
17. At the AROM prompt, enter md 300000 and press ENTER. Information like the following is displayed:
00300000 00000000 CDCDCDCD 00000000 00000000 ................
00300010 00000000 00000000 00000000 00000000 ................
AROM>
Look for the CDCDCDCD value. If this value is not displayed, examine the other drives within the
LUN until you find this value. Two drives within the LUN should contain this information.
18. At the AROM prompt, type mm 300004 and press ENTER. Information like the following is displayed:
003000004 CDCDCDCD?
19. Enter 0. (zero-period) and press ENTER. The AROM> prompt is displayed.
20. Type g and press ENTER. The following message and prompt are displayed:
Effective address: 0xFFF05198
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Test Complete
Hit any key to continue
21. Press ENTER to display the Diagnostic Menu.
22. Select 13 ("Disk Menu") to Display the Disk Menu.
23. Select 3 (“Disk Write”).
Enter the disk ID for the disk that was selected in Step 8.
24. At the “Enter # sectors” prompt, enter 1.
25. Enter memory address 0x00300000.
26. At the "Enter starting sector (HEX)" prompt, enter 3003. This sector is displayed in Step 10. The following
prompt is displayed:
Do you wish to continue? (y/n) [y]
27. Press ENTER to select the default (y).
28. Enter y to continue. The following message and prompt are displayed:
Test Complete
Hit any key to continue
29. Press ENTER to display the Disk Menu.
The first disk in the LUN has now been cleared. Follow Steps 8 through 27 for the next drive in the LUN.
After the second disk in the LUN has been cleared, the cache dirty condition should be cleared.
30. Power down the array and reinsert the other SP if that was how you disabled the second SP. Power the array
back up. The LUN should now be accessible. If the LUN is still not accessible, reboot the server.
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