SmartX recently announced that its distributed block storage product SMTX ZBS has achieved the VMware vSphere® Storage APIs for Array Integration (VAAI) Block Certification. This enables SmartX to provide more efficient services to its customers by preventing the overhead on ESXi and improving overall performance.

VMware vSphere® Storage APIs for Array Integration (VAAI), also referred to as hardware acceleration or hardware offload APIs, define a set of storage primitives that enable the ESXi host to offload cross-datastores movements, for example, storage-intensive operations such as taking snapshots, cloning, block zeroing, etc., to the array. The use of VAAI will increase the efficiency of data copy and reduce the occupation of computing resources and bandwidth. The VAAI Block Certification is specifically issued to distributed block storage products.

With the VAAI Block Certification, SMTX ZBS could use VAAI Block and offload certain storage operations from ESXi hosts to SMTX ZBS storage arrays when providing storage services for VMware ESXi through iSCSI protocol. This reduces resource overhead on the ESXi hosts and can significantly improve the operations’ performance.

Currently, SmartX has achieved the VAAI Block Certification and provides full support of VAAI Block, which includes Full Copy, Block Zero, UNMAP, Hardware Assisted Locking and Thin Provisioning Stun.

  • Full Copy: VAAI Block enables the SMTX ZBS to make full copies of data within the array without having the ESXi host read and write the data. This operation reduces the time and network load when cloning virtual machines, creating virtual machines from a template, or migrating virtual machines with storage vMotion. Since the data is not transmitted through the network, the Full Copy operation could reduce the occupation of computing resources and bandwidth.
  • Block Zero: VAAI Block enables SMTX ZBS storage arrays to zero out a large number of blocks to provide newly allocated storage. This operation reduces the time and network load when creating virtual machines and formatting virtual disks.
  • UNMAP: When a virtual machine was migrated to another datastore or deleted, ESXi immediately calls UNMAP and reclaims the space on SMTX ZBS storage arrays, preventing the waste of storage. 
  • Hardware Assisted Locking: When updating the metadata, the Hardware Assisted Locking supports discrete virtual machine locking without use of SCSI reservations. This operation allows disk locking per sector, instead of the entire LUN as with SCSI reservations, which protects the integrity of VMFS volumes and reduces I/O latency. The introduction of Hardware Assisted Locking mitigates the contention issues with SCSI reservations and enables VMFS volumes to scale to much larger sizes.
  • Thin Provisioning Stun: SMTX ZBS could better monitor and control thin-provisioned datastores with the help of Thin Provisioning Stun. If a thin-provisioned datastore’s usage reaches 100%, only those virtual machines requiring extra storage space are paused; those not needing additional space continue to run. 

About SMTX ZBS:SMTX ZBS is a VMware Ready storage solution and is now listed on the VMware Marketplace. As a distributed block storage product, it provides storage services with features such as high availability, high performance, scalability, and easy maintenance for large-scale virtualization, private clouds and container environments. Learn more about SMTX ZBS at

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