Pure Storage Cloud Dedicated on Azure: An intro to Performance
Introduction With Pure Storage Cloud Dedicated on Microsoft Azure, performance is largely governed by three factors that need to be taken into consideration: front-end controller networking, controller back‑end connection to managed disks, and the Purity data path. This post explains how Azure building blocks and these factors influence overal performance. Disclaimer: This post requires basic understanding of PSC Dedicated architecture. Real-life Performance varies based on configuration and workload; examples here are illustrative. Architecture: the building blocks that shape performance Cloud performance often comes from how compute, storage, and networking are assembled. PSC Dedicated deploys two Azure VMs as storage controllers running the Purity operating environment and uses Azure Managed Disks as persistent media. Initiator VMs connect over the Azure Virtual Network using in‑guest iSCSI or NVMe/TCP. Features like inline data reduction, write coalescing through NVRAM, and an I/O rate limiter help keep the array stable and with predictable performance under saturation. Front-end performance: networking caps Azure limits the outbound (egress) bandwidth of Virtual Machines. Each Azure VM has a certain network egress cap assigned and cannot send out more data than what the limit allows. As PSC Dedicated controllers run on Azure VMs, this translates into the following: Network traffic going INTO the PSC Dedicated array - writes - not throttled by Azure outbound bandwidth limits Network traffic going OUT of the PSC Dedicated array - reads - limited User-requested reads (e.g. from an application) as well as any replication traffic leaving the controller share the same egress budget. Because of that, planning workloads with replication should be done carefully to avoid competing with client reads. Back-end performance: VM caps, NVMe, and the write path The Controller VM caps Similarly to frontend network read throughput, Azure enforces per‑VM limits on total backend IOPS and combined read/write throughput. The overall IOPS/throughput of a VM is therefore limited by the lower of: the controller VM's IOPS/throughput cap and the combined IOPS/throughput of all attached managed disks. To avoid unnecessary spend due to overprovisioning, managed disks of PSC Dedicated arrays are configured as to saturate the controller backend caps just right. NVMe backend raises the ceiling Recent PSC Dedicated releases adopt an NVMe backend on supported Azure Premium SSD v2 based SKUs, increasing the controller VM’s backend IOPS and bandwidth ceilings. The disk layout and economics remain the same while the array gains backend headroom. The write path Purity secures initiator writes to NVRAM (for fast acknowledgment) and later destages to data managed disks. For each logical write, the backend cap is therefore tapped multiple times: a write to NVRAM a read from NVRAM during flush and a write to the data managed disks Under mixed read/write non-reducible workloads this can exhaust the combined read/write backend bandwidth and IOPS of the controller VM. Raised caps of the NVMe backend help here. Workload characteristics: iSCSI sessions and data reducibility Block size and session count Increasing iSCSI session count between Initiator VMs and the array does not guarantee better performance; with large blocks, too many sessions can increase latency without improving throughput, especially when multiple initiators converge on the same controller. Establish at least one session per controller for resiliency, then tune based on measured throughput and latency. Data reduction helps extend backend headroom When data is reducible, PSC Dedicated writes fewer physical bytes to backend managed disks. That directly reduces backend write MBps for the same logical workload, delaying the point where Azure’s VM backend caps are reached. The effect is most pronounced for write‑heavy and mixed workloads. Conversely, non‑reducible data translates almost 1:1 to backend traffic, hitting limits sooner and raising latency at high load. Conclusion Predictable performance in the cloud is about aligning architecture and operations with the platform’s limits. For PSC Dedicated on Azure, that means selecting the right controller and initiator VM SKUs, co‑locating resources to minimise network distance, enabling accelerated networking, and tuning workloads (block size, sessions, protocol) to the caps that actually matter. Inline data reduction and NVMe backend extend headroom meaningfully (particularly for mixed workloads) while Purity’s design keeps the experience consistent. Hopefully, this post was able to shed light on at least some of the performance factors of PSC Dedicated on Azure.Pure Cloud Block Store is now Pure Storage Cloud Dedicated (PSC Dedicated)
Pure Storage Cloud Dedicated: Name Change, Same Enterprise-Grade Experience Pure Storage Cloud is an enterprise-grade block storage delivered as a service in the public cloud. It extends the data services and evergreen architecture of the Purity operating system and can be deployed in: Azure as a fully managed native service or a customer-managed service integrated with Azure VMware Solution (AVS) AWS as a customer-managed service integrated with Elastic VMware Service (EVS) What’s New? Pure Cloud Block Store, the customer-managed service, is being renamed Pure Storage Cloud Dedicated (PSC Dedicated). This change reflects its integration into the Pure Storage Cloud family and alignment with the Enterprise Data Cloud strategy. What’s Not Changing? Everything That Matters Your experience, performance, and features remain the same. Pure Storage Cloud Dedicated continues to provide: Enterprise Data Services: Purity software in Azure and AWS, with data reduction, thin provisioning, and snapshots. Cost Efficiency: Optimized storage usage and reduced footprint through data reduction. Reliability & Resilience: Built-in redundancy, high availability, and cyber resilience. Hybrid & Multi-Cloud Mobility: Consistent APIs and replication across FlashArrays and PSC Dedicated for migration, DR, and data mobility. Disaster Recovery & Backup: Asynchronous and near-synchronous replication, plus snapshots for cost-effective backup and rapid recovery. VMware Workload Support: Enterprise-grade storage for VMware in AVS and EVS environments. Why This Matters The shift from Pure Cloud Block Store to Pure Storage Cloud Dedicated unifies offerings under the Pure Storage Cloud umbrella while advancing the broader Enterprise Data Cloud strategy.Purely Cloud Podcast - CBS on Azure Technical Deep Dive
Together with vjirovsky we hosted a podcast episode where we discussed CBS on Azure architecture and best practices. Have a listen here: https://soundcloud.com/user-917746545/purely-cloud-guest-series-cbs-on-azure-technical-deep-dive-and-deployment-best-practicesUse CBS as persistent storage on AKS via Portworx CSI driver
Hi all, with the recent version of Portworx CSI driver (v25.4.0) you can mount a persistent block volume on CBS into your containers on Kubernetes and utilize all features and benefits of CBS. Sharing my recent blog post, how to set it up on Azure Kubernetes Service (AKS): https://blog.vjirovsky.cz/portworx-csi-with-aks-with-cbs/VMware Data Mobility on AWS
This quick technical demo shows how fast you can put data to work in AWS and Elastic VMware Service (EVS) by linking both platforms to Pure Cloud Service on AWS. After cold-migrating a SQL VM to EVS with VMware HCX, we attach its vVols data volume to a VM in EVS via the Pure Storage vSphere Plugin, then use a few clicks in the Cloud Block Store GUI to snapshot, clone, and mount a different database volume to an Amazon EC2 instance over in-guest iSCSI. https://youtu.be/hBeV1mkDPLA?si=w_1OC3NkXZHG0i0gCBS 6.8.7 released
This version brings several updates to Cloud Block Store on both AWS and Azure. Automatic Capacity Upgrade for CBS on Azure enables customers to automatically increase total CBS capacity by adding additional storage to the array when total used storage capacity reaches the threshold of 80%. Along with the Automatic Capacity Upgrade, we released Selectable Initial Capacity, which allows customers to choose the array capacity during initial deployment. Starting from this release it’s possible to configure NVMe-TCP connection between CBS on AWS and AWS Linux based native VMs. NVMe-TCP is seen as the modern successor to iSCSI for block storage, particularly for workloads demanding high performance. Both CBS AWS and CBS Azure now support over-the-wire encryption capability for arrays that are replicating using synchronous connections, adding to the existing support for encrypted asynchronous replication. For more details, please refer to Purity Release Notes.
March 2025 | Cloud Block Store Updates!
What’s new in Pure Cloud Block Store CBS 6.8.4 released This version is bringing multiple Purity OS improvements shared across on-premise FlashArray and Pure Cloud Block Store. For more details, please refer to Purity Release Notes. Tip of the Month For CBS documentation requests, you can use a new workflow available directly from this Slack channel. Just click Workflows on top of the window - select Cloud Documentation Request - fill out the form, and we’ll take care of the rest. Blogs Pure Cloud Block Store with Cirrus Migrate Cloud, part 1 - read here Pure Cloud Block Store with Cirrus Migrate Cloud, part 2 - read here Podcasts Purely Cloud episode 4 - Living with Pure Cloud Block Store - listen here Purely Cloud episode 5 - Bridging Worlds with Azure VMware Solution - listen hereHave you considered using Cloud Block Store on Azure?
Have you considered using Cloud Block Store on Azure? Why or why not? New this month, our CBS team released Automatic Capacity Expansion. Dive into step-by-step technical demonstrations on Automatic Pure Cloud Block Store Capacity Expansion on Azure with Kyle Grossmiller. Automatic Pure Cloud Block Store Capacity Expansion on Azure: Part 1 Automatic Pure Cloud Block Store Capacity Expansion on Azure: Part 2Do you see any benefits in adopting a cloud-like purchasing model for storage?
Do you see any benefits in adopting a cloud-like purchasing model for storage? Why or why not? Curious about how Universal Credits could change your approach to storage? Pure Storage introduces Universal Credits—a flexible, cost-efficient way to manage storage needs with the ease of a cloud-like purchasing experience. Check it out!
