Based on the EMC Advisory, there’s severity high critical
issue (Potential Data Unavailability) for the VNX systems running
Operating Environment for Block 05.32.000.5.219 and earlier &
05.33.006.5.102 and earlier / Current Version -
05.33.000.2.081
Data may intermittently be unavailable due to either a dual
Storage Processor (SP) restart or a Non-Disruptive Upgrade (NDU) which does not
complete due to a single or dual Storage Processor restart.
ISSUE
A restart occurred due to bug check [05900000
FF_ASSERT_PANIC]
Event message that is seen in the System Event logs:
A 04/15/15
10:54:36 DGSSP 76008106 The Storage Processor rebooted unexpectedly @ 10:38:27
on 04/15/2015: BugCheck 0,
{0000000000000000,
0000000005900000, 000000000000010e, 0000000000000000}, Failing Instruction:
0xfffff88195e4733b in disktarg.sys loaded @ 0xfffff88195e3e000 76008106
[FF_ASSERT_PANIC]
Environment
EMC Hardware: VNX5100
EMC Hardware: VNX5300
EMC Hardware: VNX5500
EMC Hardware: VNX5700
EMC Hardware: VNX7500
EMC Hardware: VNX5200
EMC Hardware: VNX5400
EMC Hardware: VNX5600
EMC Hardware: VNX5800
EMC Hardware: VNX7600
EMC Hardware: VNX8000
CAUSE
The CAS command is used in the Hardware Assisted Locking
Mechanism (VAAI). Hardware Assisted Locking is the elimination of this
LUN-level locking based on SCSI reservations. Initially, the ESX server reads
the lock.
If the lock is free, the server sends a CAS command with the
lock data that the server wants to place into the lock and the original free contents
of the lock. The storage array reads the lock again and compares the current
data
in the lock to the Compare And Write command. If the
information matches, the new data is written to the lock. This process is
treated as a single atomic operation and is applied at the block level (not the
LUN level) allowing parallel
Virtual Machine File System (VMFS) updates possible. Atomic
Test and Set (ATS) is the VMware implementation of the SCSI CAS command.
Workaround
Disable VAAI CAS commands on the ESX Server. This command is
used by VMware hosts vSphere 4.1 and later:
VMware usage of Compare and Swap is disabled with the
following command line:
esxcfg-advcfg -s 0 /VMFS3/HardwareAcceleratedLocking
To verify the setting of this variable:
0 = disabled, using old style SCSI reservations for locking;
1 = enabled and using CAS for locking.
This command takes effect immediately. It is non-disruptive.
No host restart is required.
This command must be done on all ESX servers that are
connected to the array to stop CAS commands being sent to the array