Compellent SC is a proven, hybrid block array for classic storage workloads on a reasonable budget, while PowerStore is an enterprise-class native NVMe platform for virtualization, databases, and low-latency-sensitive environments. If you're building a new environment or planning a modernization meant to last for years, the direction is PowerStore. If you need a solid array for stable workloads without overpaying, SC still makes sense.
Below, we break both platforms down by their components – architecture, performance, scalability, support status, and migration path – so you know not just how they differ, but which one fits your specific scenario.
What is Compellent SC, and what is it good for?
The SC Series (Storage Center, formerly Compellent) is a hybrid, virtualized block array from the generation before native NVMe. Its defining feature is Data Progression – automatically moving "hot" data to a faster tier, and cold data to a cheaper one. Flexibility is considerable: the array can run in configurations from 0% to 100% flash, and the fastest tier typically takes up only 10–30% of capacity, since that's enough to cover active data.
Despite its age, SC has mature enterprise mechanisms. Distributed spare (from SCOS 7.3 onward) rebuilds the array after a drive failure up to 500% faster than classic hot spare, since it reconstructs data in parallel across multiple drives. On top of that comes Live Migrate – a free tool for moving volumes between SC arrays with no downtime – and synchronous replication in two modes (high availability and high consistency). An example model, the SC4020, is a 2U enclosure with 7–24 2.5" SAS drive bays and two redundant controllers.
Worth knowing about one limitation when choosing a model: 32Gb Fibre Channel is only supported by the SC5020, SC7020, and SC9000, and FCoE only by the SC8000 and SC9000. If you're planning specific connectivity, the model needs to be chosen carefully – you'll find available variants in our Dell Compellent array range (including the SC5020 and SC7020).
How much capacity actually remains usable on SC?
This question comes up in every quote – because the RAID level determines how much of the drives you buy you actually get to use. On the SC Series, the range is wide: RAID 10 gives 50% of capacity, while RAID 5-9 gives as much as 89%. An analysis of thousands of Dell deployments found that for a typical RAID 10/RAID 5 mix at tier 1, average efficiency comes out to around 77%.
Capacity efficiency depends on the RAID level. Data: Dell EMC, SC Series Best Practices.
The second thing worth understanding when designing for performance is the write penalty. To achieve 20,000 IOPS with a 70/30 mix and a 32K block size, the design needs to target roughly 26,000 IOPS – and on 15K spinning disks (around 200 IOPS per drive), that means as many as 130 drives. SSDs deliver up to 100x more IOPS per drive, which shows why newer platforms are built around flash and NVMe.
How does PowerStore differ from Compellent?
PowerStore is architecturally a different league entirely. It's a native NVMe platform built around microservices (containers), with machine learning built into the system. The key difference versus SC is a truly active-active dual-node architecture – both controllers handle I/O simultaneously, so no hardware sits idle as a standby.
Three things Compellent didn't have, which decide the choice for new deployments.
- Native NVMe-oF – full end-to-end NVMe over Fibre Channel (32Gb) and NVMe/TCP, alongside classic iSCSI and FC. This means genuinely lower latency for databases and virtualization.
- AppsON – the ability to run applications as virtual machines directly on the array (built-in VMware ESXi), with performance close to bare metal.
- Predictive analytics – after 15 days of collecting data, the system forecasts when capacity will run out, before it becomes a problem.
On top of that come hard numbers. Under its Future-Proof program, Dell guarantees a 5:1 data reduction ratio and effective capacity of up to 6.1 PBe per array, while measured availability reaches 99.9999%. Scalability also addresses SC's old limitation – PowerStore scales up to four node pairs (8 controllers). Importantly, an independent Evaluator Group report notes that the architecture partly builds on the proven Unity platform, which reduces the technology risk typical of a system built from scratch. You'll find the models in our Dell PowerStore range – from the 500T to the 5200T.
Compellent SC and PowerStore – side by side
|
Feature |
Compellent SC |
PowerStore |
|
Architecture |
hybrid, block-based (pre-NVMe) |
native NVMe, microservices |
|
Controllers |
two redundant |
active-active, both handle I/O |
|
NVMe-oF |
none |
NVMe/FC 32Gb + NVMe/TCP |
|
Applications on the array |
no |
AppsON (VMware ESXi) |
|
Scalability |
limited (midrange) |
up to 4 node pairs (8 controllers) |
|
Availability / reduction |
no reduction guarantee |
99.9999%; 5:1 guarantee |
|
Who it's for |
stable workloads, budget |
virtualization, databases, new deployments |
Is it still worth investing in Compellent SC?
The answer depends on the specific model, not the series as a whole. Dell distinguishes three dates in its support matrix – End of Life, End of Standard Support, and End of Entitlement (EOE) – and EOE can fall as much as three years after the EOL date. In other words: a given SC array can remain under support long after its formal "end of life." This topic is common enough that Dell partners publish dedicated guides on "SC End-of-Life – what now."
Based on our experience, SC still makes sense for stable, predictable workloads – file servers, backup, classic block storage – where cost and reliability matter more than the lowest possible latency. For new virtualization environments and databases, it's more sensible to go straight to PowerStore, so you're not modernizing the platform again in two years.
What does migrating from SC to PowerStore look like?
Dell designed PowerStore specifically with customers moving off older platforms, including SC, in mind. The agentless import method requires only a single, brief downtime window – limited to reconfiguring file systems and datastores to point to the new volumes. Making this easier, when migrating from SC, both iSCSI and Fibre Channel are supported (unlike migration from PowerMax, where only FC works).
PowerStore also includes built-in migration tools dedicated to SC Series, Unity, PS Series, and VNX sources, and Dell's internal testing points to minimal effort when moving volume groups. For a company, this means modernization doesn't have to be a painful, weeks-long project.
Which platform should you choose?
The rule is simple. New environment, virtualization, SQL databases, need for low latency and room to grow for years? PowerStore. Stable, predictable workloads and a limited budget, with infrastructure already running on SC? Compellent SC still holds up – and can be migrated smoothly later on.
Choosing the right array, RAID level, and media depends on what actually needs to run on it. Tell us what workload you're planning – ERP, SQL, virtualization, backup – and we'll select the platform and configuration for that scenario. Every one we deliver is tested, ready to deploy, and covered by warranty, with room to expand. You'll find the full selection among our disk arrays, including all-flash arrays.
FAQ
What's the difference between PowerStore and Compellent SC?
PowerStore is a native NVMe platform with an active-active architecture, NVMe-oF support, and the ability to run applications directly on the array (AppsON). Compellent SC is an older, hybrid block array without native NVMe, but still solid for classic workloads.
Is it still worth buying Compellent SC?
Yes, for stable workloads on a limited budget. Support status depends on the specific model – End of Entitlement can fall as much as three years after the End of Life date, so a given array may remain supported longer than expected.
Is migrating from SC to PowerStore difficult?
No. Dell designed PowerStore for migration from older platforms. The agentless import method requires only a single, brief downtime window, and when migrating from SC, both iSCSI and Fibre Channel are supported.
How much capacity remains usable on the SC Series?
It depends on the RAID level – from 50% with RAID 10 up to 89% with RAID 5-9. For a typical RAID 10/RAID 5 mix, average efficiency is around 77%.
Which should you choose for virtualization and databases?
PowerStore. Native NVMe, an active-active architecture, and low latency are a better fit for virtualization workloads (VMware, Hyper-V) and SQL databases than SC's hybrid architecture.
Sources
- Dell EMC – SC Series: Performance and Availability Best Practices – https://dl.dell.com/manuals/common/sc-series-performance-availability-best-practices-dell-emc-4024-bp-sc_en-us.pdf
- Dell – SC4020 Storage System Owner's Manual – https://dl.dell.com/topicspdf/dell-compellent-sc4020_owners-manual_en-us.pdf
- Dell EMC – SC Series: Synchronous Replication (CML1064) – https://dl.dell.com/manuals/common/dell-emc-sc-series-sync-replication-live-volume.pdf
- Dell – SC Series: Software Release, Support Policy and End of Life Matrix – https://downloads.dell.com/manuals/common/sc-series-software-release-support-policy-and-eol-matrix-4866-sc-wp_en-us.pdf
- tdinsight.at – SC-Series End-of-Life: What Now? (Dell partner guide) – https://www.tdinsight.at/wp-content/uploads/2021/06/SC-Series_End-of-Life_Was-nun.pdf
- Dell – PowerStore: Introduction to the Platform (White Paper) – https://resources.ampheo.com/static/datasheets/dell/powerstore-1000t.pdf
- Dell – PowerStore: Best Practices Guide – https://www.delltechnologies.com/asset/en-us/products/storage/industry-market/h18241-dell-powerstore-best-practices-guide.pdf
- Dell – PowerStore Data Sheet – https://www.ccsmedia.com/wp-content/uploads/Dell-powerstore-data-sheet.pdf
- Dell – PowerStore: Clustering and High Availability (White Paper) – https://www.delltechnologies.com/asset/en-us/products/storage/industry-market/h18157-dell-powerstore-clustering-high-availability.pdf
- Dell – PowerStore: Importing External Storage to PowerStore Guide – https://objects.icecat.biz/objects/mmo_124820730_1749659519_4376_3192577.pdf
- Evaluator Group – Dell EMC PowerStore (independent analyst report) – https://futurumgroup.com/wp-content/uploads/documents/EGL2_Dell_EMC_PowerStore-7.pdf




























































































