Advanced Storage Management

Storage is usually the most critical part of a virtual infrastructure, due to the need for enough performance and capacity for the entire cluster and all the workloads inside it. In order to provide features such as vSphere High Availability (HA), vSphere Distributed Resource Scheduler (DRS), and other cluster-related capabilities, you need common shared storage for all the ESXi hosts of the cluster. You can also have more storage per cluster, or use the same storage for more clusters.

This chapter details the storage part of a virtual infrastructure, starting from local block-based storage and extending into shared block storage with FC, FCoE and iSCSI protocols and NFS-based NAS storage.

In this chapter, we will learn more about:

• How storage is changing with new technologies
• Which type of storage VMware vSphere can use and how to configure and manage...

Storage basics

There are different types of storage, with different protocols, different architectures, different scaling, different capabilities, and also different purposes.

In a virtual environment, you will need a resilient and reliable storage solution, with the expected performance, that can scale for the future. This can only be possible using enterprise storage products, with some exceptions for the ROBO and SMB scenarios, as discussed in Chapter 2, Design and Plan a Virtualization Infrastructure.

Enterprise-class storage can be classified in different ways, but usually different acronyms are used, such as:

• Direct Attached Storage (DAS)
• Network Attached Storage (NAS)
• Storage Area Network (SAN)
• Content Addressable Storage (CAS)/Fixed Content Storage (FCS)
• Object-based storage/cloud storage

For VMware vSphere, the first three storage classes are the most relevant and the...

The evolution of the storage world

Storage-related technologies have been changing really fast in recent years and flash memory is totally redefining the storage offering, both in the architectures, as described previously, and also on the effective components where data is stored.

Spinning disks

Just 10 years ago (but we could also say just a little over 5 years ago), the different tiers described previously were usually filled with the following types of storage:

• Tier 0: 15K RPM Serial-Attached SCSI (SAS) disks
• Tier 1: 10K RPM SAS disks
• Tier 2: 7K RPM SATA or nearline disks
• Tier 3: Usually tapes

Traditional Hard Disk Drives (HDD) were the standard components for storage arrays, and more were used both for redundancy and...

VMware vSphere storage types

VMware vSphere supports different types of storage architectures, both internally (in this case the controller is crucial, that must be in the HCL) or externally with shared SAS DAS, SAN FC, SAN iSCSI, SAN FCoE, or NFS NAS (in those case the HCL is fundamental for the external storage, the fabric elements, and the host adapters).

For local storage, with vSphere 6.x it's possible to use USB disks, not only as boot disks, but also to run VMs. But note that USB datastores are just unsupported by VMware.

Storage types at the VM logical level

There are different types of virtual disks depending on the provisioning method, pre-allocated or dynamic. The type of virtual disks are mainly the same since...

VMware vSphere storage configuration

For shared storage, the ESXi configuration varies a lot depending both on the storage type and the protocols used. There is a specific guide from VMware, but what's more important is to follow the specific storage vendor guides, including possible reference architectures or configuration suggestions.

Storage FC

FC is an entire high-speed network stack used to implement storage area networks. Starting with vSphere 6.0U2, ESXi supports 32 Gbps FC for all the supported HBA.

When using ESXi with FC SAN, follow the recommendations and best practices of both VMware and the storage vendor to avoid possible issues. Note that storage vendor specifications could be more restrictive than VMware...

Storage features

The new vSphere 6.5 version, brings a lot of improvements at storage level and some new features in different areas, from VMs, to datastores, to low-level storage, as we will discuss in the next paragraphs.

VM snapshots

VM snapshots usage will be discussed in Chapter 8, Advanced VM and Resource Management, but there are some interesting improvements starting with vSphere 6.0. To perform a snapshot deletion process, the mirror driver (introduced in vSphere 5 to improve storage vMotion) is used, so that the changes to the VM are written to the active VMDK and the base disk during consolidation.

This should not only speed up the consolidation process (in the client this is called a delete snapshot, but formally...

Storage integration

VMware vSphere has several different types of storage integration solutions and technologies, some started in version 4.1 (such as VAAI), others more recently (such as VVol), directed towards building a fully software-defined storage (SDS) stack.

VMware vSphere Storage Policy Based Management (SPBM)

SPBM is an extension of the VM Storage Policies and the foundation of the SDS control vision from VMware. SPBM enables vSphere administrators to simplify storage provisioning and management, by assigning to each virtual machine the required storage features and capabilities. VM will be automatically provisioned on the right datastore that respects these requirements.

SPBM interprets the different storage requirements...

Storage design

Choosing the right storage according to your needs could be a very long debate without a simple answer, because there are so many different types of storage solutions. As usual, you have to consider availability, scalability, performance, and manageability aspects, including some new capabilities such as data protection, data migration, security, and so on.

Traditional IOPS sizing could be too limited considering that most of the enterprise storage works with concepts more complex, such as data tiering, data reduction, and data locality; for this reason, it's always suggested you make a capacity and performance estimation using vendor-specific tools.

In most cases you will have storage with some flash technologies:

• AFA (full flash): This is where performance and storage latency could be critical and you want a storage with predictable throughput and latency...

Introduction to HCI and vSAN

HCI are specific solutions that combine computing and storage (and sometimes also networking) capabilities from more hosts, to have a shared pool of resources. A vSphere cluster already does this for the computing part. Some storage products extend this to the storage part, making more external storage unnecessary, and making the HCI market a relevant trend; it is not only growing fast, with more attention from the big storage vendors, but it is also changing fast.

Some HCI products compatible with vSphere 6.5:

• Nutanix: This is the pioneer of HCI, actually it is the only solution that can work with all the hypervisor technologies (VMware vSphere, Microsoft Hyper-V, KVM with the custom AHV, Citrix Xen Server).
• HPE SimpliVity: In January 2017, HPE acquired Simplivity to bring HCI into its portfolio. Available since April, the HPE SimpliVity 380 (based...

Caching with vSphere Flash Read Cache

Flash Read Cache (vFlash) is a feature, introduced in vSphere 5.5 and available in the Enterprise Plus edition, that can improve virtual machine storage performance by using host local flash devices as a cache. The performance boost depends on your workload type and working set size. Only read-intensive workloads, with working sets that fit into the cache size, can really benefit from the Flash Read Cache feature. vSphere Flash Read Cache offers legacy support for the swap-to-SSD feature introduced in vSphere 5.0; that was a previous way to use a local SSD to host VM-related swap files.

You can reserve a Flash Read Cache for any individual virtual disk that is created only when a virtual machine is powered on; it is discarded when a virtual machine is suspended or powered off. When you migrate a virtual machine, you can migrate the cache ...

Summary

This chapter was dedicated to the storage part of a virtual infrastructure, starting from local block-based storage and extending into shared block storage with FC, FCoE, and iSCSI protocols and NFS-based NAS storage.

For each of them, we considered the different optimization techniques, integration, and storage features provided by vSphere. Other types of storage architectures were also considered, especially HCI solutions. To learn more, a great source of information for storage aspects is the VMware StorageHub at https://storagehub.vmware.com/.

In this chapter, we introduced the main storage concepts and features, described how to manage local, block, and NAS storage and how to configure vSphere to use them. Also, we explained how to integrate vSphere with storage using VAAI, VASA, vVols, storage profiles, vCenter plugins, and so on.

In the final part, there was a short...