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VCAP-DCA Study guide – 6.4 Troubleshooting Storage Performance and Connectivity

Knowledge

  • Recall vicfg-* commands related to listing storage configuration
  • Recall vSphere 4 storage maximums
  • Identify logs used to troubleshoot storage issues
  • Describe the VMFS file system

Skills and Abilities

  • Use vicfg-* and esxcli to troubleshoot multipathing and PSA‐related issues
  • Use vicfg-module to troubleshoot VMkernel storage module configurations
  • Use vicfg-* and esxcli to troubleshoot iSCSI related issues
  • Troubleshoot NFS mounting and permission issues
  • Use esxtop/resxtop and vscsiStats to identify storage performance issues
  • Configure and troubleshoot VMFS datastores using vmkfstools
  • Troubleshoot snapshot and resignaturing issues

Tools

There’s obviously a large overlap between diagnosing performance issues and tuning storage performance, so check section 3.1 in tandem with this objective.

Recall vicfg-* commands related to listing storage configuration

  • vicfg-scsidevs
  • vmkiscsi-tool
  • vicfg-mpath
  • vicfg-iscsi
  • esxcli corestorage | nmp | swiscsi
  • vicfg-nas
  • showmount -e
  • esxtop/resxtop
    • look for CONS/s – this indicates SCSI reservation conflicts and might indicate too many VMs in a LUN. This field isn’t displayed by default (press ‘f’ then ‘f’ again to add it)
  • vscsiStats
  • vmkfstools
  • vicfg-module

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