6.0.1
Table Of Contents
- vSphere Storage
- Contents
- About vSphere Storage
- Updated Information
- Introduction to Storage
- 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 Requirements
- ESXi iSCSI SAN Restrictions
- Setting LUN Allocations for iSCSI
- Network Configuration and Authentication
- Set Up Independent Hardware iSCSI Adapters
- About Dependent Hardware iSCSI Adapters
- Dependent Hardware iSCSI Considerations
- Configure Dependent Hardware iSCSI Adapters
- About the Software iSCSI Adapter
- Modify General Properties for iSCSI Adapters
- Setting Up iSCSI Network
- 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 Refresh and Rescan Operations
- Identifying Device Connectivity Problems
- Edit Configuration File Parameters
- Enable or Disable the Locator LED on Storage Devices
- Working with Flash Devices
- About VMware vSphere Flash Read Cache
- Working with Datastores
- Understanding VMFS Datastores
- Understanding Network File System Datastores
- Creating Datastores
- Managing Duplicate VMFS Datastores
- Upgrading 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
- Raw Device Mapping
- Working with Virtual Volumes
- Virtual Machine Storage Policies
- Upgrading Legacy Storage Profiles
- Understanding Virtual Machine Storage Policies
- Working with Virtual Machine Storage Policies
- Creating and Managing VM Storage Policies
- Storage Policies and Virtual Machines
- Default Storage Policies
- Assign Storage Policies to Virtual Machines
- Change Storage Policy Assignment for Virtual Machine Files and Disks
- Monitor Storage Compliance for Virtual Machines
- Check Compliance for a VM Storage Policy
- Find Compatible Storage Resource for Noncompliant Virtual Machine
- Reapply Virtual Machine Storage Policy
- Filtering Virtual Machine I/O
- VMkernel and Storage
- 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
- Storage Thick and Thin Provisioning
- Using Storage Providers
- Using vmkfstools
- vmkfstools Command Syntax
- vmkfstools Options
- -v Suboption
- File System Options
- Virtual Disk Options
- Supported Disk Formats
- Creating a Virtual Disk
- Example for Creating a Virtual Disk
- Initializing a Virtual Disk
- Inflating a Thin Virtual Disk
- Removing Zeroed Blocks
- Converting a Zeroedthick Virtual Disk to an Eagerzeroedthick Disk
- Deleting a Virtual Disk
- Renaming a Virtual Disk
- Cloning or Converting a Virtual Disk or RDM
- Example for Cloning or Converting a Virtual Disk
- Migrate Virtual Machines Between DifferentVMware Products
- Extending a Virtual Disk
- Upgrading Virtual Disks
- Creating a Virtual Compatibility Mode Raw Device Mapping
- Example for Creating a Virtual Compatibility Mode RDM
- 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
- Index
Conguration changes to avoid this problem involve making sure several input Ethernet links are not
funneled into one output link, resulting in an oversubscribed link. When a number of links transmiing near
capacity are switched to a smaller number of links, oversubscription is a possibility.
Generally, applications or systems that write a lot of data to storage, such as data acquisition or transaction
logging systems, should not share Ethernet links to a storage device. These types of applications perform
best with multiple connections to storage devices.
Multiple Connections from Switch to Storage shows multiple connections from the switch to the storage.
Figure 12‑3. Multiple Connections from Switch to Storage
1 Gbit
1 Gbit
1 Gbit
1 Gbit
Using VLANs or VPNs does not provide a suitable solution to the problem of link oversubscription in
shared congurations. VLANs and other virtual partitioning of a network provide a way of logically
designing a network, but do not change the physical capabilities of links and trunks between switches.
When storage trac and other network trac end up sharing physical connections, as they would with a
VPN, the possibility for oversubscription and lost packets exists. The same is true of VLANs that share
interswitch trunks. Performance design for a SANs must take into account the physical limitations of the
network, not logical allocations.
Checking Ethernet Switch Statistics
Many Ethernet switches provide dierent methods for monitoring switch health.
Switches that have ports operating near maximum throughput much of the time do not provide optimum
performance. If you have ports in your iSCSI SAN running near the maximum, reduce the load. If the port is
connected to an ESXi system or iSCSI storage, you can reduce the load by using manual load balancing.
If the port is connected between multiple switches or routers, consider installing additional links between
these components to handle more load. Ethernet switches also commonly provide information about
transmission errors, queued packets, and dropped Ethernet packets. If the switch regularly reports any of
these conditions on ports being used for iSCSI trac, performance of the iSCSI SAN will be poor.
Chapter 12 Best Practices for iSCSI Storage
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