Reservation conflict: Still getting messages after applying 5.1SP1Rp2 to the cluster nodes

Reservation conflict: Still getting messages after applying 5.1SP1Rp2 to the cluster nodes

  • Article ID:100006747
  • Last Published:
  • Product(s):InfoScale & Storage Foundation

Problem

After upgrading system to 5.1SP1RP2 to resolve 'Reservation conflict' messages, it was found that these messages were still being generated.
From the vxdisk_e_list
emc0_0b7d auto:cdsdisk disk1 diskgroup1 online
emc0_0b7f auto:cdsdisk disk2 diskgroup2  online

Error Message

From the DMP events log:
  4753  Sun Oct  9 00:12:05.124: SCSI error occured on Path sdba: opcode=0x5f reported reservation conflict (status=0xc, key=0x0, asc=0x0, ascq=0x0)
  4754  Sun Oct  9 00:12:05.125: SCSI error occured on Path sdax: opcode=0x5f reported unit attention (status=0x1, key=0x6, asc=0x2a, ascq=0x5)        
  4755  Sun Oct  9 00:12:05.125: SCSI error occured on Path sday: opcode=0x5f reported unit attention (status=0x1, key=0x6, asc=0x2a, ascq=0x5)        
  4758  Sun Oct  9 00:12:05.129: SCSI error occured on Path sdau: opcode=0x5f reported unit attention (status=0x1, key=0x6, asc=0x2a, ascq=0x5)        
  4761  Sun Oct  9 00:12:07.415: SCSI error occured on Path sdaw: opcode=0x5f reported reservation conflict (status=0xc, key=0x0, asc=0x0, ascq=0x0)  
  4763  Sun Oct  9 00:12:07.423: SCSI error occured on Path sdas: opcode=0x5f reported reservation conflict (status=0xc, key=0x0, asc=0x0, ascq=0x0)  
  4765  Sun Oct  9 00:12:07.426: SCSI error occured on Path sdat: opcode=0x5f reported reservation conflict (status=0xc, key=0x0, asc=0x0, ascq=0x0)     

From system logs:

 

Nov 13 21:07:33 sprs1950a0-27 vxvm:vxconfigd: V-5-1-11401 : dg import with I/O fence enabled
Nov 13 21:07:33 sprs1950a0-27 vxvm:vxconfigd: V-5-1-11401 datadg: dg import with I/O fence enabled
Nov 13 21:07:33 sprs1950a0-27 kernel: sd 1:0:1:1: reservation conflict
Nov 13 21:07:33 sprs1950a0-27 kernel: sd 1:0:1:3: reservation conflict
Nov 13 21:07:33 sprs1950a0-27 kernel: sd 1:0:1:4: reservation conflict
Nov 13 21:07:33 sprs1950a0-27 kernel: sd 1:0:1:2: reservation conflict
 

 

Solution

Customer has a VCS configuration with SCSI3 fencing enabled and configured.

When VCS onlines a diskgroup resource it will use the "groupreserve" option with the command `vxdg import`. As part of the DiskGroup Agent VCS online operation we will register keys on the data disks that are being imported. During the import and registration of the key you will see "reservation conflict". This is expected behaviour. Once the keys are registered you will no longer see the "reservation conflict" messages.

Note: Manually importing a diskgroup without specifically using the option "groupreserve" will not result in message "reservation conflict" this is because import of a local diskgroup will not automatically register keys when SCSI fencing enabled. Please see man page for vxdg specifically the groupreserve option definition and the difference between local and shared diskgroup behaviour when fencing is enabled.

 The  -o groupreserve=fence_key option specifies the I/O fencing key for a disk group. If the -o verify
                 option is also specified, the import of a private disk group fails if the SCSI-3 PR keys have not been
                 registered  on all the paths to the disks.  This ensures that a host is not fenced off while importing
                 the disk group, and that two nodes cannot attempt to fence the disk group at the same time.

                 When importing a private disk group on which I/O fencing is enabled, the -o groupreserve  option  must
                 be  used to specify the I/O fencing key explicitly.  The specified I/O fencing key, fence_key, must be
                 no longer than 7 bytes.

                 When importing a shared disk group on which I/O fencing is enabled, there is no need  to  specify  the
                 key  explicitly provided that the appropriate I/O fencing licenses have been installed, and that clus-
                 ter-wide fencing has been enabled.  The I/O fencing key is automatically created on import.
 


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