VMware’s Nathan Small who works as a Staff Engineer at Global Support Services has put together a great presentation about Advanced Root Cause Analysis. The presentation was designed to give you more insight into how a VMware Technical Support Engineer reviews logs, gathers data and performs in-depth analysis. Nathan is hoping to show you the skills they’re using every day to help determine the root cause for an issue in your environment. With this core knowledge, you will become more self-sufficient within your own environment and be able to diagnose an issue as it occurs rather than after the damage has been done.

1. Advanced Root Cause Analysis Nathan Small Staff Engineer Global Support Services Rev B – September 13, 2010

2. Today we will learn how to fish

3. Advanced Root Cause Analysis Gathering Information Log Analysis Further Analysis Comparative Analysis

4. Logging Information VMkernel Logging: Location: /var/log/vmkernel (ESX Classic) or /var/log/messages (ESXi) Purpose: This log file contains informational messages, alerts, and warnings for various pieces of code that execute via the vmkernel. It also contains log entries dumped from module logging (Qlogic, Emulex, S/W iSCSI, etc) Iterations: By default, this log has 36 rotations excluding the base log (vmkernel to vmkernel.36) Related logs: Alert and warning VMkernel events are copied to /var/log/vmkwarning Service Console Logging (ESX Classic) Location: Various logs under /var/log/ Purpose: These logs would also appear in RHEL and contain the same type of log information you would expect from that OS (aside from vprobs in ESX 4.0) Log files: boot, secure, messages, rpm, etc

5. Logging Information Hostd Logging: Location: /var/log/vmware Purpose: This log contains entries from hostd operations including NFC (network file copy) operations. Iterations: By default, this log has 10 rotations which wrap (hostd-0 to hostd-9). Pay attention to the timestamp of the log to determine which log you wish to review Vpxa Logging Location: Various logs under /var/log/vmware/vpx Purpose: This log contains requests/communication between the host and vCenter or vCenter and the host Iterations: By default, this log has 10 rotations which wrap (vpxa-0 to vpxa-9). Pay attention to the timestamp of the log to determine which log you wish to review

6. Logging Information Esxcfg-boot Logging: Location: /var/log/vmware Purpose: This log contains esxcfg-boot command information and results from the esxcfg-boot command when it is run. Iterations: There are 4 log iterations

7. HBA driver logging options By default, the HBA driver logging levels are not verbose. Increasing the logging levels can make a significant difference in finding root cause as well as resolution time for a case: Default logging: vmkernel: 0:00:22:39.107 cpu1:4270)NMP: nmp_CompleteCommandForPath: Command 0x2a (0x410001103280) to NMP device "naa.600508b40006f6930000a000021b0000" failed on physical path "vmhba1:C0:T10:L54" H:0x2 D:0x0 P:0x0 Possible sense data: 0x0 0x00x0. vmkernel: 0:00:22:39.107 cpu1:4270)WARNING: NMP: nmp_DeviceRequestFastDeviceProbe: NMP device "naa.600508b40006f6930000a000021b0000" state in doubt; requested fast path state update... vmkernel: 0:00:22:39.107 cpu1:4270)ScsiDeviceIO: 747: Command 0x2a to device "naa.600508b40006f6930000a000021b0000" failed H:0x2 D:0x0 P:0x0 Possible sense data: 0x0 0x00x0. vmkernel: 0:00:22:39.107 cpu1:4270)NMP: nmp_CompleteCommandForPath: Command 0x2a (0x41000112bc80) to NMP device "naa.600508b40006f6930000a000021b0000" failed on physical path "vmhba1:C0:T10:L54" H:0x2 D:0x0 P:0x0 Possible sense data: 0x0 0x00x0. vmkernel: 0:00:22:39.107 cpu1:4270)ScsiDeviceIO: 747: Command 0x2a to device "naa.600508b40006f6930000a000021b0000" failed H:0x2 D:0x0 P:0x0 Possible sense data: 0x0 0x00x0.

8. HBA driver logging options Enhanced Qlogic driver logging: vmkernel: 0:00:22:39.107 cpu1:4270)<6>scsi(1:10:54) UNDERRUN status detected 0x15-0x18. resid=0x0 fw_resid=0x10000 cdb=0x2a os_underflow=0x10000 vmkernel: 0:00:22:39.107 cpu1:4270)scsi(1:0:10:54) Dropped frame(s) detected (10000 of 10000 bytes)...retrying command. vmkernel: 0:00:22:39.107 cpu1:4270)<6>scsi(1:10:54) UNDERRUN status detected 0x15-0x18. resid=0x0 fw_resid=0x10000 cdb=0x2a os_underflow=0x10000 vmkernel: 0:00:22:39.107 cpu1:4270)scsi(1:0:10:54) Dropped frame(s) detected (10000 of 10000 bytes)...retrying command. vmkernel: 0:00:22:39.107 cpu1:4270)NMP: nmp_CompleteCommandForPath: Command 0x2a (0x410001103280) to NMP device "naa.600508b40006f6930000a000021b0000" failed on physical path "vmhba1:C0:T10:L54" H:0x2 D:0x0 P:0x0 Possible sense data: 0x0 0x00x0. vmkernel: 0:00:22:39.107 cpu1:4270)WARNING: NMP: nmp_DeviceRequestFastDeviceProbe: NMP device "naa.600508b40006f6930000a000021b0000" state in doubt; requested fast path state update...

9. HBA driver logging options A review of /proc/scsi/qla2xxx/X: QLogic PCI to Fibre Channel Host Adapter for QLE2460: Firmware version 4.04.09 [IP] [Multi-ID] [84XX] , Driver version 8.02.01-k1-vmw39 BIOS version 2.02 FCODE version 2.00 EFI version 2.00 Flash FW version 4.03.01 ISP: ISP2432 Login retry count = 008 Execution throttle = 2048 ZIO mode = 0x6, ZIO timer = 1 Commands retried with dropped frame(s) = 40541

10. HBA driver logging options Here are the instructions to increase HBA logging levels for ESX 4: To enable enhanced logging for Qlogic FC (qla2xxx driver): # esxcfg-module -s ql2xextended_error_logging=1 qla2xxx To enable enhanced logging for Emulex FC (lpfc840 driver) ** : # esxcfg-module -s lpfc_log_verbose=1043 To enable enhanced logging for QlogiciSCSI (qla4xxx driver): # esxcfg-module -s extended_error_logging=1 qla4xxx ** Emulex logging options can be tricky. Please refer to KB 1005576

11. List/Load Module Parameters To list all loaded modules on an ESX host, use the vmkload_mod command: # vmkload_mod -l Name R/O Addr Length R/W Addr Length ID Loaded vmklinux 0x880000 0x20000 0x28a9b80 0x4d000 1 Yes ioat 0x8a0000 0x3000 0x28f6ba0 0x3000 2 Yes ata_piix 0x8a3000 0xb000 0x28f9bc0 0x4000 3 Yes bnx2 0x8ae000 0x10000 0x28fdbe0 0x17000 4 Yes aacraid_esx30 0x8be000 0x10000 0x2914c00 0x9000 5 Yes e1000 0x8ce000 0x2a000 0x291dc20 0xd000 6 Yes qla2300_707_vmw 0x8f8000 0x5c000 0x292ac80 0xb3000 7 Yes <Snip>

12. List/Load Module Parameters To list all module parameters for a specific module, use vmkload_mod with the '-s' flag: # vmkload_mod -s qla4xxx vmkload_mod module information input file: /usr/lib/vmware/vmkmod/qla4xxx.o Version: Version 5.01.00-k8_rh5.2-01_vmw_2009_03_30, Build: 208167, Interface: 9.0, Built on: Nov 8 2009 Parameters: heap_max: int Maximum attainable heap size for the driver. heap_initial: int Initial heap size allocated for the driver. ka_timeout: int Keep Alive Timeout recovery_tmo: int Recovery Timeout cmd_timeout: int Command Timeout extended_error_logging: int Option to enable extended error logging, Default is 0 - no logging, 1 - debug logging

13. List/Load Module Parameters To set a loadable module parameter, use esxcfg-module (Persistent across reboots): # esxcfg-module –s extended_error_logging=1 qla4xxx *Note: Ensure you enter the module parameter correctly otherwise the module will fail to load on boot. This action will append a line to the bottom of /etc/vmware/esx.conf in the form of the following: <Snip> /upgrades/complete[0000]/name = "depricatePrettyName" /upgrades/complete[0001]/name = "moduleLineReformat" /upgrades/complete[0002]/name = "enableTSO310" /upgrades/complete[0003]/name = "persistVmkNicName" /vmkernel/module/qla4xxx.o/options = "extended_error_logging=1“

14. List/Load Module Parameters After the loadable module parameter is set, the boot image needs to be rebuilt (ESX Classic only) and the host needs to be rebooted for the changes to take effect (or the module can be reloaded, however we do not support this action): # esxcfg-boot –b # reboot To enable an option immediately without rebooting (non-persistent across reboots), you can echo the same parameter to the proc nodes. This may not work for all modules however it has been proven to work for FC modules: # echo "ql2xextended_error_logging=1" > /proc/scsi/qla2xxx/z z = HBA # Note: This would be particularly useful if you are troubleshooting an issue live and need more information without rebooting the host which may clear the condition.

15. Serial line logging/Remote Syslog/vMA While logging options for modules are plentiful, it may be necessary to setup serial line logging or remote syslog for an ESX host in the event that logging is missing or inconsistent. Three good examples of when this would be useful would be: 1. If the ESX host hangs unexpectedly and no logs are generated for the event, 2. The service console goes into a read-only state, 3. The local raid controller or hardware experiences an issue causing logging to not be written down to disk. The vMA appliance can be used for remote syslog purposes but is more useful with an ESXi environment in which logs are not preserved on a reboot. Setting up the vMA appliance should be mandatory for any and all ESXi hosts. To do this, each ESXi host needs to be setup as a vi-fastpass target on the vMA appliance.

16. Serial line logging/Remote Syslog/vMA Instructions on how to setup serial line logging: http://kb.vmware.com/kb/1003900 Instructions on how to setup remote syslog: http://articles.techrepublic.com.com/5100-22_11-5285872.html Instructions on how to setup ESXi host logging with vMA:http://www.simonlong.co.uk/blog/2010/05/28/using-vma-as-your-esxi-syslog-server/

17. Force crash of VM/ESX host When enhancing logging levels isn’t providing enough information or we need a deeper look at what the driver is doing in memory, it is sometimes necessary to crash a VM or the ESX host to review that memory dump. There are multiple options to capture a memory dump however it will depend on what level the memory dump needs to be seen: Memory inside the Guest OS: Taking a snapshot of the VM with memory state saved or force the OS to crash (E.g.: use the ctrl+scroll+scroll function for Windows) Memory dump of the VMM: Use vm-support to list the WID and force crash the VM with the “-X” option. This will generate a vmx-dump file for consumption. Memory dump of the ESX host: Issue an NMI from a remote administrator adapter (ie: HP iLO) which will panic the host if the host is setup correctly.

18. Force crash of VM/ESX host continued Run the following commands to immediately enable the NMI trap: Note: This does not make the change in behavior persist across a reboot.For ESX 3.x:echo 1 > /proc/sys/kernel/unknown_nmi_panicecho 1 > /proc/sys/kernel/mem_nmi_panic For ESX 4.x:echo 1 > /proc/sys/kernel/panic_on_unrecovered_nmiecho 1 > /proc/sys/kernel/unknown_nmi_panic

19. Force crash of VM/ESX host continued In order to have this change persistent across reboots, edit the file /etc/sysctl.conf and add the following lines to persist across reboots:For ESX 3.x:kernel.unknown_nmi_panic = 1kernel.mem_nmi_panic = 1For ESX 4.x:kernel.panic_on_unrecovered_nmi = 1kernel.unknown_nmi_panic = 1

20. Force crash of VM/ESX host continued VMware ESXi 3.xThere is no configurable option for ESXi 3.x to change the behaviour of ESXi when receiving an NMI. To observe the hang/crash event within the logs, prior to the failure, press Alt+F12 at the console to display the VMkernel log. VMware ESXi 4.xRun the following command followed by a reboot of the host:esxcfg-advcfg -k 2 nmiAction

21. Corruption messages in vmkernel log When corruption occurs it can be useful to review the logs from the host that saw the corruption occur. These messages will usually indicate what volume saw corruption, what type of corruption was seen, and what part of the VMFS structure experienced corruption (offset): Heartbeat Region Corruption:WARNING: Swap: vm 1086: 2268: Failed to open swap file '/volumes/4730e995-faa64138-6e6f-001a640a8998/foo/foo-560e1410.vswp': Invalid metadataFSS: 390: Failed with status Invalid metadata for f530 28 1 46ee2036 61d5698d 4004b12 f4c3b923 0 0 0 0 0 0 0 FS3: 6710: Reclaiming timed out heartbeat [HB state abcdef02 offset 3313664 gen 3 stamp 21824288493247 uuid 4a2ff95d-7967268a-db5c-001a64ca3e46 jrnl <FB 59001> drv 7.33] failed: Invalid metadata

22. Corruption messages in vmkernel log File Lock Corruption:vmkernel: Invalid lock address 0[lockAddr 0] Invalid lock type 0x0[lockAddr 496217088] Invalid lock addrWARNING: FS3: 556: Volume 4bef2afb-b8226400-2f20-0019b9b5a27b (“vmfs1") may be damaged on disk. Corrupt lock detected at offset 1d93ac00: [type 0 offset 0 v 0, hb offset 0WARNING: FS3: 7544: Volume 4beeef00-3222e0e8-c25f-0019b9b5a27b (“storevmdk") may be damaged on disk. Corrupt lock detected at offset ad419e4ead419e4d: [type a88c4fa2 offset 12484433702799121997 v 12484433870302846580, h

23. Corruption messages in vmkernel log Cluster/Resource Group Corruption:WARNING: Fil3: 4165: Unknown object type 0 WARNING: Fil3: 4165: Unknown object type 1314280013WARNING: Fil3: 9613: Found invalid object on 49e752ba-4d3c56e8-a7fd-0015177af4b7 <FD c0 r0> expected <FD c92 r125>

24. Corruption messages in vmkernel log The code still relies on some sanity when pasting these types of corruption messages. As such, there are instances where the logged message will state corruption offsets that are completely out of range:WARNING: FS3: 7544: Volume 4beeef00-3222e0e8-c25f-0019b9b5a27b (“storevmdk") may be damaged on disk. Corrupt lock detected at offset ad419e4ead419e4d: [type a88c4fa2 offset 12484433702799121997 v 12484433870302846580, h As you can see, these ranges do not conform to the expected value ranges.

25. VMFS Corruption (volume dump for analysis) There are varying degrees of data required to successfully troubleshoot/resolve corruption in the VMFS structure depending on what has gotten corrupt. To simply address the HeartBeat region, 25M will suffice. To address the file lock regions, up to 1.2GB would be required. To gather a disk dump for review with VMware Support, please refer to the instructions in KB 1009565:http://kb.vmware.com/kb/1009565

26. Advanced Root Cause Analysis Gathering Information Log Analysis Further Analysis Comparative Analysis

27. Log format Logging in vSphere is quite verbose as is but it is important to know what you are looking at when doing a root cause analysis. In this section we will review the logging format for: /var/log/vmkernel and /var/log/vmkwarning /var/log/vmksummary /var/log/vmkiscsid.log /var/log/messages

28. vmkernel/vmkwarning The vmkernel log is your primary resource for logging messages when trying to determine root cause. By default this log will have 36 rotated iterations plus the base vmkernel log (vmkernel to vmkernel.36) with the exception of ESXi logging, which places all messages into /var/log/messages. The best way to quickly review the vmkernel log messages for an ESXi host would be to run the following command: # cat messages* |grepvmkernel|less There is a secondary log file known as vmkwarning which has an iteration of 4 plus the base log file (vmkwarning to vmkwarning.4). This log file parses the vmkernel log for any messages with a status of WARNING or ALERT. Here would be an example of each: WARNING: SCSI: 4623: Manual switchover to vmhba2:1:30 completed unsuccessfully. ALERT: APIC: 1150: Lint1 interrupt on pcpu 0 (port x61 contains 0x91)

29. vmkernel/vmkwarning Here is a breakdown of all fields in a standard vmkernel/vmkwarning log message: Nov 30 16:04:17 esx04vmkernel:28:02:20:33.356cpu4:1586)StorageMonitor:196:vmhba2:0:0:0 status = 0/7 0x0 0x00x0 Nov 30 16:04:17 = Date and time esx04 = server name vmkernel: = logging type 28:02:20:33.356 = uptime of host (days:hours:minutes:seconds:milliseconds) cpu4: = cpu/core that trapped the message 1586) = World ID or WID of process StorageMonitor: = Piece of code reporting message 196: = line of code reporting the message vmhba2:0:0:0 status = 0/7 0x0 0x00x0= message content

30. vmkernel/vmkwarning Not all vmkernel log messages appear exactly in this fashion. When a driver dumps its logging output to the vmkernel log, there is less uniform formatting involved: Nov 30 16:04:17 esx04 vmkernel: 28:02:20:33.356 cpu4:1720)<4>lpfc2:0749:FPe:Completed Abort Task Set Data: x0 x0 x128 Nov 30 16:04:17 = Date and time esx04 = server name vmkernel: = logging type 28:02:20:33.356 = host uptime cpu4: = cpu that trapped the message 1720) = WID of process <4>lpfc2:0749:FPe:Completed Abort Task Set Data: x0 x0 x128 = driver logging (non-uniform)

31. vmkernel/vmkwarning Here are another two driver logging examples (both are from Qlogic FC driver): May 13 02:02:44 esx02 vmkernel: 0:01:11:59.660 cpu1:1064)scsi(0): Waiting for LIP to complete... May 13 02:02:44 esx02 vmkernel: 0:01:11:59.660 cpu0:1064)<6>qla2x00_fw_ready ha_dev_f=0xc

32. vmksummary The vmksummary log file is quite useful since it will log the top 3 processes running in memory at the first minute of every hour but it will also indicate if there was a bad host shutdown as well as if a PSOD occurred. This log will show if a kernel (COS or vmkernel) stops responding. Here is a logging example of when a simple user initiated host reboot: Nov 2 11:01:06 rtpesx04 logger: (1257177666) hb: vmk loaded, 11302248.49, 11302235.731, 27, 153875, 153875, 0, ftAgent-89872, vmware-h-80764, webAcces-58600 Nov 2 11:13:50 rtpesx04 logger: (1257178430) unloaded VMkernel Nov 2 11:14:27 rtpesx04 vmkhalt: (1257178467) Rebooting system... Nov 2 13:46:13 rtpesx04 vmkhalt: (1257187573) Starting system... Nov 2 13:46:19 rtpesx04 logger: (1257187579) loaded VMkernel Nov 2 14:01:03 rtpesx04 logger: (1257188463) hb: vmk loaded, 976.32, 963.584, 16, 153875, 153875, 0, vmware-h-71508, webAcces-69084, snmpd-30204

33. vmkiscsid.log The vmkiscsid.log log file is a new log file as of vSphere and will only be logged to if the software initiator is used. 2010-01-11-06:59:44: iscsid: Nop-out timedout after 10 seconds on connection 42:0 state (3). Dropping session. 2010-01-11-06:59:47: iscsid: Kernel reported iSCSI connection 46:0 error (1008) state (3) 2010-01-11-06:59:47: iscsid: connection42:0 is operational after recovery (2 attempts)

34. messages The format for messages is no different than that of standard logging for any Linux distribution: Jan 24 00:01:01 esx6 syslogd 1.4.1: restart. It is important to know what information we populate in this log. One such object would be the vprobs logging, a new feature introduce in vSphere: Jan 24 00:11:21 esx6 vobd: Jan 24 00:11:21.656: 3552646292992us: [vprob.vmfs.heartbeat.timedout] 49fdca7e-4d680d70-51f7-0015c5f29bb6 SAN006-T3-PC2-001-RP-V5. Jan 24 00:11:23 esx6 vobd: Jan 24 00:11:23.592: 3552648228889us: [vprob.vmfs.heartbeat.recovered] 49fdca7e-4d680d70-51f7-0015c5f29bb6 SAN006-T3-PC2-001-RP-V5.

35. Tracing a command Over the years we have added layers of management to our product. As a result, a single operation changes hands several times from start to finish. It is important to understand this process flow when troubleshooting why an operation fails or times out. The main components involved in a single operation could be the following: VI Client Virtual Center (vpxd) SQL Database Host connect agent for VC (vpxa) Hostd Vmkernel ESX Service Console HBAs/NICs/Physical Components of the Host

36. Tracing a command Here is how the process flows for a simple rescan:1. User initiates rescan in VI Client2. VI Client sends rescan request to ESX host (vpxa) 3. vpxa sends rescan request to hostd4. hostd sends request to vmkernel5. vmkernel sends rescan to HBA driver 6. HBA driver updates vmkernel with new/existing LUN information 7. vmkernel updates hostd8. hostd hands LUN information to vpxa9. vpxa updates VI Client

37. Tracing a command VI Client Log (C:ocuments and SettingsSERNAMEocal Settingspplication DataMwarepxiclient-#.log): [viclient:SoapTran] 2010-06-23 10:21:39.929 Invoke 82 Start RescanAllHba on HostStorageSystem:storageSystem-19961 [bs-tse-vc40.bsl.vmware.com]. [Caller: VpxClient.HostConfig.StorageRescanRequestManager.RescanAllHba] [viclient:SoapTran] 2010-06-23 10:21:44.460 Invoke 82 Finish RescanAllHba on HostStorageSystem:storageSystem-19961 [bs-tse-vc40.bsl.vmware.com] - Serial:0.001, Server:004.528 [viclient:SoapTran] 2010-06-23 10:21:44.460 Invoke 85 Start RescanVmfs on HostStorageSystem:storageSystem-19961 [bs-tse-vc40.bsl.vmware.com]. [Caller: VpxClient.HostConfig.StorageRescanRequestManager.OnSingleRescanComplete] [viclient:SoapTran] 2010-06-23 10:21:46.241 Invoke 85 Finish RescanVmfs on HostStorageSystem:storageSystem-19961 [bs-tse-vc40.bsl.vmware.com] - Serial:0.000, Server:001.735

38. Tracing a command Host VC agent Log (/var/log/vmware/vpxa/vpxa.log): [2010-06-23 10:36:48.794 0x134cab90 info 'App'] [VpxLRO] -- BEGIN task-internal-6871 -- -- vim.host.StorageSystem.rescanAllHba -- 52dc67f5-a2d1-af98-67f1-6bdf9f335997 [2010-06-23 10:36:50.055 0x134cab90 info 'App'] [VpxLRO] -- FINISH task-internal-6871 -- -- vim.host.StorageSystem.rescanAllHba -- 52dc67f5-a2d1-af98-67f1-6bdf9f335997 [2010-06-23 10:36:53.354 0x13446b90 info 'App'] [VpxLRO] -- BEGIN task-internal-6873 -- -- vim.host.StorageSystem.rescanVmfs -- 52dc67f5-a2d1-af98-67f1-6bdf9f335997 [2010-06-23 10:36:53.764 0x13446b90 info 'App'] [VpxLRO] -- FINISH task-internal-6873 -- -- vim.host.StorageSystem.rescanVmfs -- 52dc67f5-a2d1-af98-67f1-6bdf9f335997

39. Tracing a command Hostd Log (/var/log/vmware/hostd.log): [2010-06-23 10:36:48.795 1A6C2B90 info 'TaskManager'] Task Created : haTask-ha-host-vim.host.StorageSystem.rescanAllHba-258139 [2010-06-23 10:36:48.949 1A6C2B90 verbose 'StorageSystem'] SendStorageInfoEvent() called [2010-06-23 10:36:48.950 1A6C2B90 verbose 'Hostsvc::DatastoreSystem'] ReconcileVMFSDatastores called: refresh = true, rescan = false [2010-06-23 10:36:48.950 1A6C2B90 verbose 'FSVolumeProvider'] RefreshVMFSVolumes called <Snip> [2010-06-23 10:36:50.047 1A6C2B90 info 'TaskManager'] Task Completed : haTask-ha-host-vim.host.StorageSystem.rescanAllHba-258139 Status success

40. Tracing a command Hostd Log (/var/log/vmware/hostd.log) continued: [2010-06-23 10:36:53.355 1A6C2B90 info 'TaskManager'] Task Created : haTask-ha-host-vim.host.StorageSystem.rescanVmfs-258143 [2010-06-23 10:36:53.355 1A6C2B90 verbose 'Hostsvc::DatastoreSystem'] ReconcileVMFSDatastores called: refresh = true, rescan = true [2010-06-23 10:36:53.355 1A6C2B90 verbose 'FSVolumeProvider'] RefreshVMFSVolumes called [2010-06-23 10:36:53.355 1A6C2B90 verbose 'FSVolumeProvider'] RescanVmfs called <Snip> [2010-06-23 10:36:53.763 1A6C2B90 verbose 'Hostsvc::DatastoreSystem'] ReconcileVMFSDatastores: Done discovering new filesystem volumes. [2010-06-23 10:36:53.764 1A6C2B90 info 'TaskManager'] Task Completed : haTask-ha-host-vim.host.StorageSystem.rescanVmfs-258143 Status success

41. Tracing a command VMkernel Log (/var/log/vmkernel.log): Jun 23 10:36:48 vmkernel: 38:01:50:35.036 cpu0:5221)ScsiScan: 846: Path 'vmhba2:C1:T9:L0': Type: 0x0, ANSI rev: 2, TPGS: 0 (none) Jun 23 10:36:48 vmkernel: 38:01:50:35.056 cpu0:5221)ScsiScan: 843: Path 'vmhba3:C0:T1:L0': Vendor: 'DGC ' Model: 'RAID 5 ' Rev: '0226' <Snip> Jun 23 10:36:53 vmkernel: 38:01:50:39.663 cpu0:5221)Vol3: 1488: Could not open device '4bb2464a-b108d7a3-d785-000cfc0089f3' for probing: No such target on adapter Jun 23 10:36:53 vmkernel: 38:01:50:39.663 cpu0:5221)Vol3: 608: Could not open device '4bb2464a-b108d7a3-d785-000cfc0089f3' for volume open: No such target on adapter Jun 23 10:36:53 vmkernel: 38:01:50:39.663 cpu0:5221)FSS: 3702: No FS driver claimed device '4bb2464a-b108d7a3-d785-000cfc0089f3': Not supported

42. Advanced Root Cause Analysis Gathering Information Log Analysis Further Analysis Comparative Analysis

43. Qlogic FC driver messages Qlogic logs rather user friendly and human readable error messages. There is very little translation required when decoding these messages: vmkernel: 7:12:52:12.942 cpu1:1114)<6>qla2xxx_eh_abort(0): aborting sp 0x3e704e80 from RISC. pid=7417334 sp->state=2 vmkernel: 7:12:52:12.942 cpu1:1114)<6>qla2xxx_eh_abort(0): aborting sp 0x3e704e80 from RISC. pid=7417334 sp->state=2 vmkernel: 7:12:52:12.942 cpu1:1114)qla24xx_abort_command(0): handle to abort=735 vmkernel: 7:12:52:12.942 cpu1:1114)<6>qla24xx_abort_command(0): handle to abort=735 vmkernel: 7:12:52:50.315 cpu7:1066)qla2x00_mailbox_command(1): timeout calling abort_isp vmkernel: 7:12:52:50.315 cpu7:1066)<6>qla2x00(1): Performing ISP error recovery - ha= 0x29c3b00. vmkernel: 7:12:52:50.325 cpu7:1066)qla24xx_nvram_config(1) setting 24XX operation mode to =0x6 timer delay =0x1 us

44. Emulex FC driver messages Emulex does not take the user friendly approach however it still maintains a very high level of verbosity. It also employs a standard format that makes it easy to read and understand once you are familiar with it. Emulex publishes their error codes and how to decode them online:http://www-dl.emulex.com/support/vmware/732/vmware.pdf

45. Emulex FC driver messages VMkernel log message example:<4>lpfc2:0749:FPe:Completed Abort Task Set Data: x0x0x128 HBA = lpfc2 Emulex message ID = 0749 Driver Preamble string = FPe Message Description = Completed Abort Task Set Data field: SCSI ID = x0 LUN ID = x0 Complete time (in mS) = x128

46. Emulex FC driver messages Here is the same error when referenced against Emulex documentation<4>lpfc2:0749:FPe:Completed Abort Task Set Data: x0x0x128 elx_mes0749: Cmpl abort task set DESCRIPTION: Abort task set completed. DATA: (1) scsi_id(2) lun_id(3) cmpl time mS SEVERITY: Information LOG: LOG_FCP verbose ACTION: None required. FPe = FCP traffic history (See message log table in pdf)

47. Emulex FC driver messages Here are some other Emulex logging examples: <4>lpfc0:1305:LKe:Link Down Event x70 received Data: x70 x20 x20010200 <4>lpfc1:0250:DIe:EXPIRED nodev timer Data: x10c00 x0 xb

48. Emulex FC driver messages Let’s review each message in the Emulex documentation: <4>lpfc0:1305:LKe:Link Down Event x70 received Data: x70 x20 x20010200 Message 1305: elx_mes1305: Link Down Event <eventTag> received DESCRIPTION: A link down event was received. DATA: (1) fc_eventTag (2) hba_state (3) fc_flag SEVERITY: Error LOG: Always ACTION: If numerous link events are occurring, check the physical connections to the Fibre Channel network.

49. Emulex FC driver messages <4>lpfc0:0250:DIe:EXPIRED nodev timer Data: x10c00 x0 xb Message 0250: elx_mes0250: EXPIRED nodev timer DESCRIPTION: A device disappeared for greater than the configuration parameter (lpfc_nodev_tmo) seconds. All I/O associated with this device will fail. DATA: (1) dev_did (2) scsi_id (3) rpi SEVERITY: Error LOG: Always ACTION: Check physical connections to Fibre Channel network and the state of the remote PortID.

50. HBA Driver Source Code It is not always clear why a particular message is thrown by the driver and it may be difficult to research what the condition means either because it is not documented well or even at all. As the drivers we use in our kernel are based on the Linux open source code versions, we can download this source and manually search for a message/error. The Emulex errors we just reviewed are available in the source code under lpfc_logmsg.c The source code is available here:http://downloads.vmware.com/d/info/datacenter_downloads/vmware_vsphere_4/4#open_source * Note: The link you want is under ESX/ESXi -> OSS Source Code and is a 600M download that contains all open source packages.

51. NMP messages NMP: nmp_CompleteCommandForPath: Command 0x2a (0x4100010ead00) to NMP device "naa.6006048cb94fa67564932bcf676a406a" failed on physical path "vmhba33:C0:T0:L2" H:0x0 D:0x2 P:0x0 Valid sense data: 0x3 0x0 0x6. NMP = Code Module nmp_CompleteCommandForPath = Code Instruction Command 0x2a = SCSI Command Issued 0x4100010ead00 = Command Index naa.6006048cb94fa67564932bcf676a406a = LUN command issued to vmhba33:C0:T0:L2 = path used H:0x0 D:0x2 P:0x0 = Component Status Valid sense data: 0x3 0x0 0x6. = SCSI sense key, ASC & ASCQ info

52. NMP messages Let’s take a closer look at the SCSI information for that last error: “… failed on physical path "vmhba33:C0:T0:L2" H:0x0D:0x2P:0x0 Valid sense data: 0x30x0 0x6.” Host status = H:0x0 = Ok Device Status = D:0x2 = Check Condition Plugin status = P:0x0 = Ok SCSI Sense Key = 0x3 = MEDIUM ERROR Additional Sense Code, ASC Qualifier = 0x0/0x6 = I/O Process Terminated

53. NMP messages This information can be obtained from t10.org:

54. Advanced Root Cause Analysis Gathering Information Log Analysis Further Analysis Comparative Analysis

55. Log Field Data In the log analysis section we talked about what each field in the vmkernel log meant. Now we are going to focus on why this information is important and how you can use these values to your advantage. Knowing each value can help you with the following: Determine World ID of VM How frequently events are being logged (all the time vs. every 5 minutes) Identifying any pattern of behavior (random VMs crashing on same pcpu/core) Which code module the message came from Which exact line of code the message was generated from If subsequent messages are directly related to each other (timestamp)

56. Log Field Data: Example 1 vmkernel.log Apr 8 06:09:27 esxvmkernel: 7:12:07:20.454 cpu2:1274)VSCSI: 2803: Reset request on handle 8322 (0 outstanding commands) Apr 8 06:09:27 esxvmkernel: 7:12:07:20.454 cpu4:1061)VSCSI: 3019: Resetting handle 8322 [0/0] Apr 8 06:09:27 esxvmkernel: 7:12:07:20.454 cpu4:1061)VSCSI: 2871: Completing reset on handle 8322 (0 outstanding commands)

57. Log Field Data: Example 1 cat /proc/vmware/vm/1274/names vmid=1274 pid=-1 cfgFile="/vmfs/volumes/49bec690-6c6a8788-0b1b-0019b9d670ae/NEUBOS3ES328/NEUBOS3ES328.vmx" uuid="50 06 73 c1 c3 48 cf 28-47 ea af 1b f0 67 8e 30" displayName="NEUBOS3ES328“ vmware.log Apr 08 06:09:27.257: vcpu-0| BUSLOGIC: Soft reset 0x6cff6 Apr 08 06:09:27.257: vcpu-0| BUSLOGIC: Bus reset 0x6cff6 (0 cif) Apr 08 06:09:27.257: vcpu-0| BUSLOGIC: Sync reset target 0, handle 8322 Apr 08 06:09:27.258: vcpu-0| BUSLOGIC: Adapter reset complete 0x6cff6

58. Many Components, Many Factors When investigating an issue in the environment, it is paramount to review the logs from multiple host or even all hosts to determine if each host saw the issue the same or differently. In the event of an “all hosts except one” experienced an issue scenario, reviewing the single host that saw things different is paramount however only a cross section of the other impact hosts would be required. The reversal of this is also true for a one host experienced an issue and all other hosts were Ok.

59. Time Frame The time frame in which an event occurred is usually critical to root cause analysis. Once that time frame has be isolated, exploration into the logs of other related components (vmkiscsi.log, array controller log, hostd, etc) should be considered a next step if the conclusions in the vmkernel log aren’t conclusive enough. If multiple hosts were affected by this issue, verify this time frame against the logs from other host. If similar log entries appear for all hosts however the time is not exact (off by well over a minute), ensure that NTP is configured on the ESX hosts and is running correctly. This applies to all components of the infrastructure (switches, array, etc)

60. Conclusion This presentation was designed to give you insight into how a VMware Technical Support Engineer reviews logs, gathers data, and performs an in-depth analysis. Our hope is to show you the skills that we use every day to help you determine root cause for an issue in your environment. With this core knowledge, we hope that you will become more self sufficient within your own environment and be able to diagnose an issue as it is occurring rather than after the fact.