Dell Unity: Persistent Reservation Conflicts And ESXi Hosts

Resumen: Persistent Reservation Conflicts can cause Broadcom (VMware) ESXi servers to lose access to some Logical Unit Numbers (LUN).

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Síntomas

What Is a Persistent Reservation Conflict?

  • Persistent Reservations, as the name implies, adds application resilience to the registration groups. The purpose is to handle the failure of one (or more) hosts in a cluster. With persistent reservations, a second host can "take over" a reservation made by a failing host. Cluster software uses these kinds of reservations.
  • Often customers upgrade their cluster with software that uses the more generalized SCSI-3 reservations. All the nodes in the cluster may not be upgraded at once. Therefore, some nodes may be using older SCSI-2 reservations, whereas other nodes may be using newer SCSI-3 style reservations. This can cause problems. If the cluster node that is using the older style reservations is upgraded, its older reservations are "cleaned out" when it reboots. A solution to reservation conflict problems is to reboot the entire cluster.
  • A Reservation Conflict status generally means that the initiator that is trying to access the LUN is not allowed access because some other initiator has reserved the LUN. There are different types of reservations. Some types allow one and only one initiator to access the LUN. Other types of reservations allow a group of initiators to access the LUN but prevent any other initiators from accessing the LUN. Persistent Reservations, as the name implies, adds application resilience to the registration groups. The purpose is to handle the failure of one (or more) hosts in a cluster. With persistent reservations, a second host can "take over" a reservation made by a failing host. Cluster software uses these kinds of reservations. Often a solution to reservation conflict problems is to reboot the entire cluster.


Example from the ESXi host VMkernel log:

Oct 27 09:59:01 xxxx335 vmkernel: 0:16:39:53.731 cpu3:1040)SCSI: vm 1040: 109: Sync CR at 0
Oct 27 09:59:01 xxxx335 vmkernel: 0:16:39:53.731 cpu3:1040)WARNING: SCSI: 119: Failing I/O due to too many reservation conflicts
Oct 27 09:59:01 xxxx335 vmkernel: 0:16:39:53.731 cpu3:1040)WARNING: FS3: 2913: reservation error: SCSI reservation conflict
Oct 27 09:59:01 xxxx335 vmkernel: 0:16:39:53.731 cpu3:1040)WARNING: FS3: 3370: Failed with bad0022
Oct 27 09:59:01 xxxx335 vmkernel: 0:16:39:53.731 cpu3:1040)FSS: 390: Failed with status SCSI reservation conflict for f530 28 1 4a588dc4 6c9974b4 1        e00d266 7e9ecd0b 0 0 0 0 0 0 0

 

Example from the Dell Unity ktrace log:

  • Extracted Log Location: \spX\EMC\C4Core\log\c4_safe_ktrace.log
  • Viewing Live Using the Command Line: grep -i "PR Conflict" /EMC/C4Core/log/c4_safe_ktrace.log
B       01/26/25 11:37:15.049 TDD              4e3ff700 kt_std           Op 1A, type 5, PR Conflict for ini 2100000E1EF77C10 LUN 9CA628668DD762CD, reg 0, Port 18

 

Example from the VNX ktrace log:

A 10/28/09 17:13:31 TCD4 fd7619d0 CC 02\04\03 LUN 0x0 Initiator 10000000C9627F5C OpCode 0x00
A 10/28/09 17:13:31 TCD4 fd7619d0 CC 02\04\03 LUN 0x0 Initiator 10000000C9627F5C OpCode 0x00
A 10/28/09 17:13:31 TCD4 fd7619d0 CC 02\04\03 LUN 0x0 Initiator 10000000C9627F5C OpCode 0x00
A 10/28/09 17:13:31 TCD4 fd7619d0 CC 02\04\03 LUN 0x0 Initiator 10000000C9627F5C OpCode 0x00
A 10/28/09 17:13:31 TCD4 fd7619d0 CC 02\04\03 LUN 0x0 Initiator 10000000C9627F5C OpCode 0x00
A 10/28/09 17:13:31 TCD4 fd7619d0 CC 06\29\00 LUN 0xE Initiator 10000000C9627F5C OpCode 0x00

A 10/28/09 17:13:39 TDD 9f4836c0 Rsv6 Persistent Reservation conflict for Initiator 10000000C9627F5C LUN E Tag 32.
A 10/28/09 17:13:39 TDD 9f4836c0 Rsv6 Persistent Reservation conflict for Initiator 10000000C9627F5C LUN E Tag 345.
A 10/28/09 17:13:40 TDD 9f4836c0 Rsv6 Persistent Reservation conflict for Initiator 10000000C9627F5C LUN E Tag 157.

<<<<<<<< LUN 29 (FLU 259) trespassed to SPB and no conflicts observed >>>>>>>

A 10/28/09 17:14:39 LUSM ff24d040 Enter 259 LU_ENABLED op=LUSM_RELEASE_FOR_TRESPASS el.st=0x1901 [ShutdownRelease.ForTrespass]
A 10/28/09 17:14:39 LUSM ff24d040 Exit 259 LU_SHUTDOWN_TRESPASS op=LUSM_RELEASE_FOR_TRESPASS el.st=0x1901 [ShutdownRelease.ForTrespass]
A 10/28/09 17:14:40 LUSM ff24d040 Enter 259 LU_PEER_ASSIGN op=LUSM_ASSIGN_PEER_DONE el.st=0x0
A 10/28/09 17:14:40 LUSM ff24d040 Exit 259 LU_PEER_ENABLED op=LUSM_ASSIGN_PEER_DONE el.st=0x0
A 10/28/09 17:14:40 LUSM ff24d040 Enter 259 LU_PEER_ENABLED op=LUSM_ASSIGN_PEER_DONE el.st=0x0
A 10/28/09 17:14:40 LUSM ff24d040 Exit 259 LU_PEER_ENABLED op=LUSM_ASSIGN_PEER_DONE el.st=0x0

<<<<<<<< LUN 29 (FLU 259) trespassed back to SPA from SPB we see reservation conflicts >>>>>>>

A 10/28/09 17:21:41 LUSM ff24d040 Enter 259 LU_PEER_ENABLED op=LUSM_RELEASE_FOR_TRESPASS el.st=0x2 [Assign.StartAssign]
A 10/28/09 17:21:41 LUSM ff24d040 Exit 259 LU_PEER_SHUTDOWN_TRESPASS op=LUSM_RELEASE_FOR_TRESPASS el.st=0x2 [Assign.StartAssign]
A 10/28/09 17:21:41 LUSM ff24d040 Enter 259 LU_PEER_SHUTDOWN_TRESPASS op=LUSM_RELEASE_FOR_TRESPASS_DONE el.st=0x2 [Assign.StartAssign]
A 10/28/09 17:21:41 LUSM ff24d040 Exit 259 LU_ASSIGN op=LUSM_PROCEED_WITH_ASSIGN el.st=0x2 [Assign.StartAssign]
A 10/28/09 17:21:41 LUSM ff24d040 Enter 259 LU_ASSIGN op=LUSM_PROCEED_WITH_ASSIGN el.st=0x2 [Assign.StartAssign]
A 10/28/09 17:21:41 LUSM ff24d040 Exit 259 LU_ASSIGN op=LUSM_PROCEED_WITH_ASSIGN el.st=0x3 [Assign.GlutRead]
A 10/28/09 17:21:41 CACHE a4bb2040 Starting assignment of LUN 259
A 10/28/09 17:21:41 LUSM ff24d040 Enter 259 LU_ASSIGN op=LUSM_ASSIGN_DONE el.st=0xd [Assign.Done]
A 10/28/09 17:21:41 LUSM ff24d040 Exit 259 LU_ENABLED op=LUSM_ASSIGN_DONE el.st=0xd [Assign.Done]

A 10/28/09 17:22:13 TCD4 fd7619d0 CC 02\04\03 LUN 0x0 Initiator 10000000C9627F5C OpCode 0x00
A 10/28/09 17:22:13 TCD4 fd7619d0 CC 02\04\03 LUN 0x0 Initiator 10000000C9627F5C OpCode 0x00

A 10/28/09 17:22:21 TDD 9f4836c0 Rsv6 Persistent Reservation conflict for Initiator 10000000C9627F5D LUN E Tag 256.
A 10/28/09 17:22:21 FCDMTL 3 (FE2) fd762bf0 Target command error: loopID = 33., SCSI status = 18, instance 0
A 10/28/09 17:22:21 TDD 9f4836c0 Rsv6 Persistent Reservation conflict for Initiator 10000000C9627F5D LUN E Tag 257.
A 10/28/09 17:22:21 FCDMTL 3 (FE2) fd762bf0 Target command error: loopID = 33., SCSI status = 18, instance 0
A 10/28/09 17:22:21 TDD 9f4836c0 Rsv6 Persistent Reservation conflict for Initiator 10000000C9627F5D LUN E Tag 258.
A 10/28/09 17:22:21 TDD 9f4836c0 Rsv6 Persistent Reservation conflict for Initiator 10000000C9627F5D LUN E Tag 259.

Causa

A reservation conflict occurs when a host tries to access a LUN already reserved by another initiator, which has locked the LUN for exclusive use.

Resolución

Rebooting the owning SP which is reporting reservation conflicts should clear the conflicts and the LUN should become more accessible. However, the cause of the reservation conflict must be investigated with the host vendor.

 

Información adicional

Resolving SCSI reservation conflicts (external link)

Productos afectados

Dell EMC Unity, VNX/VNXe, Dell EMC Unity Family |Dell EMC Unity All Flash, Dell EMC Unity Hybrid, VMware
Propiedades del artículo
Número de artículo: 000108373
Tipo de artículo: Solution
Última modificación: 04 nov 2025
Versión:  5
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