VMware-vSphere5.5-Platform-Whats-New(12)

vSphere 5.5最新资料

What’s New in VMware vSphere 5.5 Platform

vSphere Storage Enhancements

Support for 62TB VMDK

VMware is increasing the maximum size of a virtual machine disk file (VMDK) in vSphere 5.5. The previous limit was 2TB—512 bytes. The new limit is 62TB. The maximum size of a virtual Raw Device Mapping (RDM) is also increasing, from 2TB—512 bytes to 62TB. Virtual machine snapshots also support this new size for delta disks that are created when a snapshot is taken of the virtual machine.

This new size meets the scalability requirements of all application types running in virtual machines.

MSCS Updates

Microsoft Cluster Service (MSCS) continues to be deployed in virtual machines for application availability purposes. VMware is introducing a number of additional features to continue supporting customers that implement this application in their vSphere environments. In vSphere 5.5, VMware supports the following features related to MSCS:

• Microsoft Windows 2012

• Round-robin path policy for shared storage

• iSCSI protocol for shared storage

• Fibre Channel over Ethernet (FCoE) protocol for shared storage

Historically, shared storage was supported in MSCS environments only if the protocol used was Fibre Channel (FC). With the vSphere 5.5 release, this restriction has been relaxed to include support for FCoE and iSCSI.

With regard to the introduction of round-robin support, a number of changes were made concerning the SCSI locking mechanism used by MSCS when a failover of services occurs. To facilitate this new path policy, changes have been implemented that make it irrelevant which path is used to place the SCSI reservation; any path can free the reservation.

16GB E2E Support

In vSphere 5.0, VMware introduced support for 16Gb FC HBAs. However these HBAs were throttled down to work at 8Gb. In vSphere 5.1, VMware introduced support to run these HBAs at 16Gb. However, there is no support for full, end-to-end 16Gb connectivity from host to array. To get full bandwidth, a number of 8Gb connections must be created from the switch to the storage array.

In vSphere 5.5, VMware introduces 16Gb end-to-end FC support. Both the HBAs and array controllers can run at 16Gb as long as the FC switch between the initiator and target supports it.

PDL AutoRemove

Permanent device loss (PDL) is a situation that can occur when a disk device either fails or is removed from the vSphere host in an uncontrolled fashion. PDL detects if a disk device has been permanently removed—that is, the device will not return—based on SCSI sense codes. When the device enters this PDL state, the vSphere host can take action to prevent directing any further, unnecessary I/O to this device. This alleviates other conditions that might arise on the host as a result of this unnecessary I/O. With vSphere 5.5, a new feature called PDL AutoRemove is introduced. This feature automatically removes a device from a host when it enters a PDL state. Because vSphere hosts have a limit of 255 disk devices per host, a device that is in a PDL state can no longer accept I/O but can still occupy one of the available disk device spaces. Therefore, it is better to remove the device from the host.

T E C H N I C A L W H I T E P A P E R/12