3PAR VAAI Plug-in 1.1.0 for VMware vSphere 4.1 Users Guide

2.2.1 Hardware Assisted Locking (ATS)

Rather than locking the entire LUN, Hardware Assisted Locking (ATS) only locks the blocks on the LUN that are allocated to the VMDK. This enhanced capability is intended to help virtualized data centers in at least two important ways.

■If you are already using or want to use larger size LUNs and place multiple VMDKs on a single LUN, you can now do so and still make clones of individual VMDK files without negatively impacting other VMDKs also located on that LUN.

■3PAR's implementation of the ATS command was done within the ASIC of its InServ Storage Servers to expedite processing of this command. While the performance benefits this provides in small environments may be too negligible to notice, large virtualized infrastructures can quickly create large numbers of clones.

3PAR’s unique implementation of Hardware Assisted Locking takes advantage of the 3PAR Gen3 ASIC to handle data comparisons in silicon with significantly higher performance and throughput. It facilitates the automatic modification of disk sectors without the use of SCSI reservations so multiple hosts can access LUNs concurrently while reducing the number of commands required to successfully acquire on-disk locks.

2.2.2 Full Copy (XCOPY)

Full Copy (XCOPY) resolves the host overhead that is associated with VMware initiating and managing cloning operations. It facilitates the cloning of individual VMDKs while keeping the overhead associated with the copy off the host and on the storage array which can significantly improve the performance of host-initiated clones.

Full Copy increases agility by reducing the amount of time required to perform common copy operations like virtual machine cloning and storage workload migrations using VMware Storage vMotion™. This is made possible by allowing the storage hardware to transparently manage large data movements, and by minimizing host, fabric and network I/O activity. With the integration of the 3PAR Gen3 ASIC and 3PAR Thin Persistence software, built-in zero- detection capabilities further speed cloning and storage workload migrations while also delivering a capacity savings benefit.

2.2.3 Block Zeroing (WRITE-SAME)

Block Zeroing (WRITE-SAME) is intended to reduce the host overhead that results when VMware zeros out disk space for Thin and Thick VMDKs and at create time for VMs.

About 3PAR VAAI Plug-in 1.1.0 for VMware vSphere 4.1

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