principal storage

In the Ultra Transcenders books

2V0-17.25

Each book explains principal storage in context, with comparison tables and the common traps.

Terms in this definition

• SWITCH

  Checks one expression against several candidate values, returning whichever result pairs with the match (or a fallback otherwise). Writing SWITCH ( TRUE (), ... ) avoids nested IF chains: whichever condition is first true wins.

• vSAN ESA

  Newer vSAN design built for NVMe, with one tier and storage pools rather than disk groups. OSA is the older design, using two tiers.

• VMFS

  Clustered file system for block datastores, whether the storage is iSCSI, local or FC-attached. Unlike VMFS5, VMFS6 can use 4Kn devices and reclaims freed space by itself.

• OVER

  Gives a T-SQL window function its window: PARTITION BY, ORDER BY and, if wanted, a ROWS or RANGE frame. Rankings and running totals can then be worked out while every row is kept.

• NFS

  Network File System, a file-sharing protocol from the Unix world, available on Azure Files, Azure NetApp Files and Blob Storage (as NFSv3).

• supplemental storage

  Extra storage attached to an existing VCF cluster, holding workloads or items like ISO images, templates and backups, as opposed to principal storage chosen while the cluster is being built. Some types, NFS 4.1 among them, are limited to this role.

Related terms

• FC

  Fibre Channel, a SAN protocol for block storage. VCF clusters may use VMFS over it as principal storage.

• Host commissioning

  Bringing ESX hosts into the SDDC Manager inventory of VCF, where they are validated and linked to a principal storage type and a network pool so clusters can use them. Decommissioning takes unassigned hosts back out.

• vSAN

  VMware's software-defined storage, which combines local devices across a cluster's ESX hosts into one shared datastore. Available as OSA or ESA, VCF can use it as principal storage.