HP 3PAR Solutions Software for vSphere - Manual (Page 6)

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.
•
HP’s implementation of the ATS command was done within the ASIC of its HP 3PAR Storage
Systems 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.
HP’s unique implementation of Hardware Assisted Locking takes advantage of the HP 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.
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 HP 3PAR Gen3 ASIC and HP 3PAR Thin Persistence Software, built-in zero-detection
capabilities further speed cloning and storage workload migrations while also delivering a capacity
savings benefit.
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.
Block Zeroing Increases performance and efficiency by eliminating the writing of zeros as data
by the host for the purpose of "cleaning" space for a VMDK. Using the WRITE-SAME command,
VMware now transfers the overhead associated with these writes to the storage array by instructing
the storage array to assume the burden of writing the zeros on these newly allocated blocks.
HP 3PAR systems then take this WRITE SAME command a step further when the blocks associated
with the VM are initialized. HP 3PAR's ASIC and its Thin Persistence software recognize the zeros
as they are written by the WRITE SAME command thus reducing system workload.
Since HP tracks which blocks on its array are zeroed out and which ones have data in them, HP
only needs to zero out the blocks with data in them. Blocks of data that do contain zeros are
unmapped so no write penalty is incurred on the HP 3PAR system.
Package Contents
You can download the installation package from the following location: http://www.hp.com/
storage/vmware
6 Overview and Features