Learn only the essentials and easily understand storage.

With the advent of virtual machines, cloud services, container technology, and Kubernetes, new options have been added to the traditional block storage, file storage, and object storage: bare metal servers, virtual machines, containers, and Kubernetes.
As a result, storage provision and operation has become easier and can now be used as a service.
This book starts with the basic concepts of storage and examines the types and structures of storage.
Additionally, we will generously share our storage operation know-how, including how to set up storage on bare metal servers/virtual machines, how to utilize it in containers/Kubernetes, essential storage monitoring and costs, and encryption management.

The data plane is a group of controllers that handle read/write operations for reading and writing data.
A network connected to this data plane is also called in-band.
Meanwhile, the control plane is a group of controllers that manipulate and configure storage resources, such as creating or deleting volumes.
Networks that connect to the control plane are also called out-of-band.

--- p.17

Many storage systems offer different remote replication features depending on the distance, such as within the same data center or over a long distance of 100 kilometers or more.
In the case of long-distance replication, compression or deduplication is sometimes performed before transmission to reduce the amount of data flowing from the source to the target.
/ For ultra-long distance replication, it may exceed the storage's remote replication support distance.
In that case, it is configured as a multihop.
Multi-hop achieves remote replication by deploying storage that acts as a relay.

--- p.44

Communication between storage and virtual machine management software uses the manufacturer's proprietary protocol or SMI-S, a storage management standard interface, as a control plane API.
Unfortunately, however, there are no standard specifications or standards for virtual machine management software, and each supports different storage management functions and operating methods.
Additionally, the virtual machine management software only provides management functions, and the actual data reading and writing is done through data plane protocols such as iSCSI and NFS.

--- p.79

Because VolumeSnapshot calls a snapshot of storage, only the differences in actually updated data are stored, enabling backups that consume less capacity.
However, depending on the storage, if the original volume (PV) is deleted, it may not be recoverable.
On the other hand, if a snapshot is created, there are storages that can restore the target volume without deleting it even if the PV is deleted.
/ As restoration conditions vary depending on the storage used, be sure to check in advance.

--- p.119

As a countermeasure against controller failure, the controller must first be made redundant.
Most appliance storage systems feature multiple controllers, enabling high availability (HA) configurations. SDS configures HA by installing components that perform each controller function on multiple servers.
/ The high availability configuration of the controller includes Active-Active configuration and Active-Standby configuration.
Which one is available varies depending on the product, so check the product's technical documentation and set it up.
Also, if possible, it would be a good idea to power each controller from a separate power source.

--- p.146

Kubernetes native storage is, as the name suggests, storage that operates on Kubernetes.
Kubernetes native storage runs containerized storage as pods on Kubernetes.
This allows you to manage storage using Kubernetes' features, such as version upgrades through rolling updates, self-healing, and scale capabilities.
/ Another feature is that many storages can be executed with Kubernetes commands without having to memorize storage-specific commands for basic operations such as version upgrades.

--- p.199