PowerFlex: The advantages of disaggregated infrastructure deployments
Mon, 17 Aug 2020 21:39:26 -0000
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For several years, there has been a big push from quite a number of IT vendors towards delivering solutions based on Hyperconverged Infrastructure or HCI. The general concept of HCI is to take the three primary components of IT, compute, network and storage, and deliver them in a software defined format within a building block, normally an x86 based server. These building blocks are then joined together to create a larger, more resilient environment. The software defined components are typically a hypervisor to provide compute, virtual adapters and switches for networking, along with some software that takes the local disks attached to the server, combines them with the disks directly attached to the other building blocks and presents them as a virtual storage system back to the environment.
The HCI approach is attractive to customers for a variety of reasons:
- Easy upgrades by just adding in another building block
- A single management interface for virtual compute, virtual networking and virtual storage
- Having one team to manage everything as it is all in one place
There are of course scenarios where the HCI model does not fit, the limitations are frequently associated with the software defined storage part of the environment, situations such as the following:
- Extra storage is required but additional compute and the associated licensing is not.
- Paying for database licensing on cores that are being used for virtual storage processes.
- Unused storage capacity within the HCI environment that is inaccessible to servers outside the HCI environment.
- A server requirement for a specific workload that does not match the building blocks deployed.
- When maintenance is required it impacts both compute and storage.
Several HCI vendors have attempted to address these points but often their solutions to the issues involve a compromise.
What if there was a solution that provided software defined storage that was flexible enough to meet these requirements without compromise?
Step forward PowerFlex, a product flexible enough to be deployed as an HCI architecture, a disaggregated architecture (separate compute and storage layers managed within the same fabric), or a mixture of the two.
So how can PowerFlex be this flexible?
It is all about how the product was initially designed and developed, it consists predominantly of three separate software components:
- Storage Data Client (SDC): The software component installed on the operating system that will consume storage. It can be thought of as analogous to a Fibre Channel adapter driver from the days of SAN interconnect storage arrays. It can be installed on a wide selection of operating systems and hypervisors, most Linux distributions, VMware and Windows are supported.
- Storage Data Server (SDS): The component that is installed on the server or virtual server providing local disk capacity, it works with other servers installed with the SDS software to provide a pool of storage from which volumes are allocated. It is generally installed on a Linux platform.
- Metadata Manager (MDM): The software management component, it ensures that SDC and the SDS components are behaving themselves and playing nicely together (parents of more than one child will understand).
Each of these components can be installed across a cluster of servers in a variety of ways in order to create flexible deployment scenarios. The SDC and SDS components communicate with one another over a standard TCP/IP network to form an intelligent fabric, this is all overseen by the MDM, which is not in the data path.
Some pictures will help illustrate this far better than I can with words.
By installing the SDC (the C in a yellow box) and the SDS (the S in a green box) on to the same server, an HCI environment is created.
If the SDC and SDS are installed on dedicated servers, a disaggregated infrastructure is created
And because PowerFlex is entirely flexible (the clue is in the name), HCI and disaggregated architectures can be mixed within the same environment.
What are the advantages of deploying a disaggregated environment?
- MAXIMUM FLEXIBILITY - Compute and storage resources can be scaled independently.
- CLOUD-LIKE ECONOMICS – following on from above – what if an application needs to cope with a sudden doubling of compute resource (for example, to cope with a one-off business event)? With a disaggregated deployment, the extra compute-only resources can be added temporarily into the environment, ride the peak demand, then retire afterwards, reducing expenditure by only using what is needed.
- MAXIMISE STORAGE UTILISATION - Completely heterogeneous environments can share the same storage pool.
- CHOOSE THE CORRECT CPU FOR THE WORKLOAD - Servers with frequency optimised processors can be deployed for database use and not require licenses for cores potentially performing processing related to storage.
- AVOID CREATING MULTIPLE ISLANDS OF SOFTWARE DEFINED STORAGE - A mixture of hypervisors and operating systems can be deployed within the same environment; VMware, Hyper-V and Red Hat Virtualisation, along with operating systems running on bare metal hardware, all accessing the same storage.
- UPDATE STORAGE & COMPUTE INDEPENDENTLY - Maintenance can be performed on storage nodes completely independently of compute nodes and vice versa, thereby simplifying planned downtime. This can dramatically simplify operations, especially on larger clusters and prevents storage and compute operators from accidentally treading on each other’s toes!
Whilst HCI deployments are ideal for environments where compute requirements and storage capacity increases remain in lockstep, there are many use cases where compute and storage needs grow independently, PowerFlex is capable of serving both requirements.
PowerFlex was built to allow this disaggregation of resources from day one, which means that there is no downside to performance or capacity when storage nodes are added to existing clusters, in fact there are only positives, with increased performance, capacity and resilience, setting PowerFlex apart from many other software defined storage products.