6.7
Table Of Contents
- vSphere Storage
- Contents
- About vSphere Storage
- Introduction to Storage
- Getting Started with a Traditional Storage Model
- Overview of Using ESXi with a SAN
- Using ESXi with Fibre Channel SAN
- Configuring Fibre Channel Storage
- Configuring Fibre Channel over Ethernet
- Booting ESXi from Fibre Channel SAN
- Booting ESXi with Software FCoE
- Best Practices for Fibre Channel Storage
- Using ESXi with iSCSI SAN
- Configuring iSCSI Adapters and Storage
- ESXi iSCSI SAN Recommendations and Restrictions
- Configuring iSCSI Parameters for Adapters
- Set Up Independent Hardware iSCSI Adapters
- Configure Dependent Hardware iSCSI Adapters
- Configure the Software iSCSI Adapter
- Configure iSER Adapters
- Modify General Properties for iSCSI or iSER Adapters
- Setting Up Network for iSCSI and iSER
- Using Jumbo Frames with iSCSI
- Configuring Discovery Addresses for iSCSI Adapters
- Configuring CHAP Parameters for iSCSI Adapters
- Configuring Advanced Parameters for iSCSI
- iSCSI Session Management
- Booting from iSCSI SAN
- Best Practices for iSCSI Storage
- Managing Storage Devices
- Storage Device Characteristics
- Understanding Storage Device Naming
- Storage Rescan Operations
- Identifying Device Connectivity Problems
- Enable or Disable the Locator LED on Storage Devices
- Erase Storage Devices
- Working with Flash Devices
- About VMware vSphere Flash Read Cache
- Working with Datastores
- Types of Datastores
- Understanding VMFS Datastores
- Upgrading VMFS Datastores
- Understanding Network File System Datastores
- Creating Datastores
- Managing Duplicate VMFS Datastores
- Increasing VMFS Datastore Capacity
- Administrative Operations for Datastores
- Set Up Dynamic Disk Mirroring
- Collecting Diagnostic Information for ESXi Hosts on a Storage Device
- Checking Metadata Consistency with VOMA
- Configuring VMFS Pointer Block Cache
- Understanding Multipathing and Failover
- Failovers with Fibre Channel
- Host-Based Failover with iSCSI
- Array-Based Failover with iSCSI
- Path Failover and Virtual Machines
- Pluggable Storage Architecture and Path Management
- Viewing and Managing Paths
- Using Claim Rules
- Scheduling Queues for Virtual Machine I/Os
- Raw Device Mapping
- Storage Policy Based Management
- Virtual Machine Storage Policies
- Workflow for Virtual Machine Storage Policies
- Populating the VM Storage Policies Interface
- About Rules and Rule Sets
- Creating and Managing VM Storage Policies
- About Storage Policy Components
- Storage Policies and Virtual Machines
- Default Storage Policies
- Using Storage Providers
- Working with Virtual Volumes
- About Virtual Volumes
- Virtual Volumes Concepts
- Virtual Volumes and Storage Protocols
- Virtual Volumes Architecture
- Virtual Volumes and VMware Certificate Authority
- Snapshots and Virtual Volumes
- Before You Enable Virtual Volumes
- Configure Virtual Volumes
- Provision Virtual Machines on Virtual Volumes Datastores
- Virtual Volumes and Replication
- Best Practices for Working with vSphere Virtual Volumes
- Troubleshooting Virtual Volumes
- Filtering Virtual Machine I/O
- Storage Hardware Acceleration
- Hardware Acceleration Benefits
- Hardware Acceleration Requirements
- Hardware Acceleration Support Status
- Hardware Acceleration for Block Storage Devices
- Hardware Acceleration on NAS Devices
- Hardware Acceleration Considerations
- Thin Provisioning and Space Reclamation
- Using vmkfstools
- vmkfstools Command Syntax
- The vmkfstools Command Options
- -v Suboption
- File System Options
- Virtual Disk Options
- Supported Disk Formats
- Creating a Virtual Disk
- Initializing a Virtual Disk
- Inflating a Thin Virtual Disk
- Converting a Zeroedthick Virtual Disk to an Eagerzeroedthick Disk
- Removing Zeroed Blocks
- Deleting a Virtual Disk
- Renaming a Virtual Disk
- Cloning or Converting a Virtual Disk or RDM
- Extending a Virtual Disk
- Upgrading Virtual Disks
- Creating a Virtual Compatibility Mode Raw Device Mapping
- Creating a Physical Compatibility Mode Raw Device Mapping
- Listing Attributes of an RDM
- Displaying Virtual Disk Geometry
- Checking and Repairing Virtual Disks
- Checking Disk Chain for Consistency
- Storage Device Options
Identifying Device Connectivity Problems
When your ESXi host experiences a problem while connecting to a storage device, the host treats the
problem as permanent or temporary depending on certain factors.
Storage connectivity problems are caused by a variety of reasons. Although ESXi cannot always
determine the reason for a storage device or its paths being unavailable, the host differentiates between a
permanent device loss (PDL) state of the device and a transient all paths down (APD) state of storage.
Permanent Device Loss
(PDL)
A condition that occurs when a storage device permanently fails or is
administratively removed or excluded. It is not expected to become
available. When the device becomes permanently unavailable, ESXi
receives appropriate sense codes or a login rejection from storage arrays,
and is able to recognize that the device is permanently lost.
All Paths Down (APD) A condition that occurs when a storage device becomes inaccessible to the
host and no paths to the device are available. ESXi treats this as a
transient condition because typically the problems with the device are
temporary and the device is expected to become available again.
Detecting PDL Conditions
A storage device is considered to be in the permanent device loss (PDL) state when it becomes
permanently unavailable to your ESXi host.
Typically, the PDL condition occurs when a device is unintentionally removed, or its unique ID changes, or
when the device experiences an unrecoverable hardware error.
When the storage array determines that the device is permanently unavailable, it sends SCSI sense
codes to the ESXi host. After receiving the sense codes, your host recognizes the device as failed and
registers the state of the device as PDL. For the device to be considered permanently lost, the sense
codes must be received on all its paths.
After registering the PDL state of the device, the host stops attempts to reestablish connectivity or to send
commands to the device.
The vSphere Client displays the following information for the device:
n
The operational state of the device changes to Lost Communication.
n
All paths are shown as Dead.
n
Datastores on the device are not available.
If no open connections to the device exist, or after the last connection closes, the host removes the PDL
device and all paths to the device. You can disable the automatic removal of paths by setting the
advanced host parameter Disk.AutoremoveOnPDL to 0.
vSphere Storage
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