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VMware vSphere vSAN vCenter Server Storage I/O Enhancements

VMware vSphere vSAN vCenter Server Storage I/O Enhancements

VMware vSphere vSAN vCenter Server Storage I/O Enhancements

This is part three of a three-part series looking at last weeks v6.7 VMware vSphere vSAN vCenter Server Storage I/O Enhancements. The focus of this post is on server, storage, I/O along with deployment and other wrap up items. In case you missed them, read part one here, and part two here.

VMware as part of updates to, vSAN and vCenter introduced several server storage I/O enhancements some of which have already been mentioned.

VMware vSphere 6.7
VMware vSphere Web Client with vSphere 6.7

Server Storage I/O enhancements for vSphere, vSAN, and vCenter include:

  • Native 4K (4kn) block sector size for HDD and SSD devices
  • Intel Volume Management Device (VMD) for NVMe flash SSD
  • Support for Persistent Memory (PMEM) aka Storage Class Memory (SCM)
  • SCSI UNMAP (similar to TRIM) for SSD space reclamation
  • XCOPY and VAAI enhancements
  • VMFS-5 is now default file system
  • VMFS-6 SESparse vSphere snapshot space reclamation
  • VVOL supporting SCSI-3 persistent reservations and IPv6
  • Reduce dependences on RDMs with VVOL enhancements
  • Software-based Fibre Channel over Ethernet (FCoE) initiator
  • Para Virtualized RDMA (PV-RDMA)
  • Various speeds and feeds enhancements

VMware vSphere 6.7 also adds native 4KN sector size (e.g., 4096 block size) in addition to traditional native and emulated 512-byte sectors for HDD as well as SSD. The larger block size means performance improvements along with better storage allocation for applications, particularly for large capacity devices. Other server storage I/O updates include RDMA over Converged Ethernet (RoCE) enabled Remote Direct Memory Access (RDMA) as well as Intel VMD for NVMe. Learn more about NVMe here.

Other storage-related enhancements include SCSI UNMAP (e.g., SCSI equivalent of SSD TRIM) with the selectable priority of none or low for SSD space reclamation. Also enhanced are SESparse of vSphere snapshot virtual disk space reclamation (for VMFS-6). VMware XCOPY (Extended Copy) now works with vendor-specific VMware API for Array Integration (VAAI) primitives along with SCSI T10 standard used for cloning, zeroing and copy offload to storage systems. Virtual Volumes (VVOL) have been enhanced to support IPv6 and SCSI-3 persistent reservations to help reduce dependency or use of RDMs.

VMware configuration maximums (e.g., speeds and feeds) including server storage I/O enhancements including boosting from 512 to 1024 LUNs per host. Other speeds and feeds improvements include going from 2048 to 4096  server storage I/O paths per host, PVSCSI adapters now support up to 256 disks vs. 64 (virtual disks or Raw Device Mapped aka RDM). Also note that VMFS-3 is now the end of life (EOL) and will be automatically upgraded to VMFS-5 during the upgrade to vSphere 6.7, while the default datastore type is VMFS-6.

Additional server storage I/O enhancements include RoCE for RDMA enabling low latency server to server memory-based data movement access, along with Para-virtualized RDMA (PV-RDMA) on Linux guest OS. ESXi has been enhanced with iSER (iSCSI Extension for RDMA) leveraging faster server I/O interconnects and CPU offload. Another server storage I/O enhancement is Software based Fibre Channel over Ethernet (e.g., SW-FCoE) initiator using loss less Ethernet fabrics.

Note as a reminder or refresher that VMware also has para (e.g., virtualization-optimized) drivers for Ethernet and other networks, NVMe as well as SCSI in addition to standard devices. For example, you can access from a VM an NVMe backed datastore using standard VMware SATA, SCSI Controller, LSI Logic SAS, LSI Logic Parallel, VMware Paravirtual, native NVMe driver (virtual machine type 6.5 or higher) for better performance. Likewise, instead of using the standard SAS and SCSI VM devices, the VMware para-virtualized

Besides the previously mentioned items, other enhancements including for vSAN include support for logical clusters such as Oracle RAC, Microsoft SQL Server Availability Groups, Microsoft Exchange Data Availability Groups as well as Windows Server Failover Clusters (WSFC) using vSAN iSCSI service. Note that as a proof point of continued vSAN deployment customer adoption, VMware is claiming 10,000 deployments. For performance, vSAN enhancement also includes updates for adaptive placement, adaptive resync, as well as faster cache destage. The benefit of quicker destage is that cache can be drained or written to disk to eliminate or prevent I/O bottlenecks.

As part of supporting expanding, more demanding enterprise among other workloads, vSAN enhancements also include resiliency updates, physical resource and configuration checks, health and monitoring checks. Other vSAN improvements include streamlined workflows, converged management views across vCenter as well as vRealize tools. Read more from VMware about server storage I/O enhancements to vSphere, vSAN, and vCenter here.

VMware Server Storage I/O Memory Matters

VMware is also joining others with support for evolving persistent memory (PMEM) leveraging so-called storage class memories (SCM). Note, some refer to SCM as persistent memory as PM, however, context needs to be used as PM also means Physical Machine, Physical Memory, Primary Memory among others. With the new PMEM support for server memory, VMware is laying the foundation for guest operating systems as well as applications to leverage the technology.

For example, Microsoft with Windows Server 2016 supports SCMs as a block addressable storage medium and file system, as well as for Direct Access (e.g., DAX). What this means is that fast file systems can be backed by persistent faster than traditional SSD storage, as well as applications such as SQL Server that support DAX can do direct persistent I/O.

As a refresher, Non-Volatile DIMM enable server memory by combing traditional DRAM with some persistent storage class memory. By combing DRAM and storage class memory (SCM) also known as PMEM servers can use the RAM as a fast read/write memory, with the data destaged to persistent memory. Examples of SCM include Micron 3D Xpoint also known as Intel Optane along with others such as Everspin NVDIMM among others (available from Dell, HPE among others. Learn more SSD and storage class memories (SCM) along with PMEM here, as well as NVMe here.

Deployment, be prepared before you grab the bits and install the software

For those of you who want or need to download the bits here is a link to VMware software download. However, before racing off to install the new software in your production (or perhaps even lab), do your homework. Read the important information from VMware before upgrading to vSphere here (e.g., KB53704) as well as release notes, and review VMware’s best practices for upgrading to vCenter here.

Some of the things to be aware of including upgrade order and dependencies, as well as make sure you have good current backups of your vSphere ESXi configuration, vCenter appliance. In addition to viewing the vSphere ESXi and vCenter 6.7 release notes here, also.

There are some hardware compatibility items you need to be aware of, both for this as well as future versions. Check out the VMware hardware (and software) compatibility list (HCL), along with partner product interoperability matrices, as well as release notes. Pay attention to devices depreciated and no longer supported in ESXi 6.7 (e.g., VMware KB52583) as well as those that may not work in future releases to avoid surprises.

Where to learn more

Learn more about VMware vSphere, vCenter, vSAN and related software-defined data center (SDDC); software-defined data infrastructures (SDDI) topics via the following links:

Additional learning experiences along with common questions (and answers), as well as tips can be found in Software Defined Data Infrastructure Essentials book.

Software Defined Data Infrastructure Essentials Book SDDC

What this all means and wrap-up

In case you missed them, read part one here and click here for part two of this series.

Some will say what’s the big deal why all the noise, coverage and discussion for a point release?

My view is that this is a big evolutionary package of upgrade enhancements and new features, even if a so-called point release (e.g., going from 6.5 to 6.7). Some vendors might have done this type of updates as a significant, e.g., version 6.x to 7.x upgrade to make more noise, get increased coverage or merely enhance the appearance of software maturity (e.g., V1.x to V2.x to V3.x, and so forth).

In the case of VMware, what some might refer to point release that is smaller, are the ones such as vSphere 6.5.0 to 6.5.x among others. Thus, there is a lot in this package of updates from VMware and good to see continued enhancements.

I also think that VMware is getting challenges from different fronts including Microsoft as well as cloud partners among others which is good. The reason I believe that it is okay VMware is being challenged is given their history; they tend to step up their game playing harder as well as stronger with the competition.

VMware is continuing to invest and extend its core SDDC technologies to meet the expanding demands of various organizations, from small to ultra large enterprises. What this means is that VMware is addressing ease of use for smaller, as well as removing complexity to enable simplified scaling from on-site (or on-premise and on-prem if you prefer) to the public cloud.

Overall the VMware Announced version 6.7 of vSphere vSAN vCenter SDDC core components are a useful extension of their existing technology. VMware Announced release 6.7 of vSphere vSAN vCenter SDDC core components enhancements enable customers more flexibility, scalability, resiliency, and security to meet their various needs.

Ok, nuff said, for now.

Cheers Gs

Greg Schulz - Microsoft MVP Cloud and Data Center Management, VMware vExpert 2010-2018. Author of Software Defined Data Infrastructure Essentials (CRC Press), as well as Cloud and Virtual Data Storage Networking (CRC Press), The Green and Virtual Data Center (CRC Press), Resilient Storage Networks (Elsevier) and twitter @storageio. Courteous comments are welcome for consideration. First published on https://storageioblog.com any reproduction in whole, in part, with changes to content, without source attribution under title or without permission is forbidden.

All Comments, (C) and (TM) belong to their owners/posters, Other content (C) Copyright 2006-2018 Server StorageIO and UnlimitedIO. All Rights Reserved. StorageIO is a registered Trade Mark (TM) of Server StorageIO.

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Greg Schulz is founder of the Server and StorageIO (StorageIO) Group, an IT industry analyst and consultancy firm. Greg has worked with various server operating systems along with storage and networking software tools, hardware and services. Greg has worked as a programmer, systems administrator, disaster recovery consultant, and storage and capacity planner for various IT organizations. He has worked for various vendors before joining an industry analyst firm and later forming StorageIO.

In addition to his analyst and consulting research duties, Schulz has published over a thousand articles, tips, reports and white papers and is a sought after popular speaker at events around the world. Greg is also author of the books Resilient Storage Network (Elsevier) and The Green and Virtual Data Center (CRC). His blog is at www.storageioblog.com and he can also be found on twitter @storageio.