DELL STORAGE SC4020 Array In An Affordable All In One Form Factor Leave a comment

Dell’s Storage SC8000 arrays deliver an impressive range of storage optimisation features but their hefty price tag puts them way beyond the reach of SMBs. That’s about to change as the new Storage SC4020 delivers the same enterprise level features but at a much lower price point.

Small review of Dell Storage sc4020

The SC4020 amalgamates everything into a compact 2U chassis with 24 hot-swap SFF drive bays. It runs exactly the same Storage Center (SC) software as its bigger brother and is designed for businesses with more modest expansion plans.

It comes as standard with dual active controllers each with 2.5GHz E3-1265L v2 Xeons and 16GB of battery protected DDR3 cache. Controllers are available with quads of 8Gbps FC ports and Dell has just announced models with dual 10GbE SFP+ ports.

The controllers have dual 6Gbps SAS expansion ports which accept its SC200 and SC220 expansion shelves. The drive count can go to 120 and Dell offers SSDs, 15k SAS, 10k SAS and NL SAS as options.

Even RAID array creation is done for you and DBA selects them to suit each tier with options for RAID0, 5, 6, 10 and the new dual-mirrored arrays. All physical storage is amalgamated into a single Disk Folder pool and the SC4020 combined with the expansion shelves can currently present a maximum pool size of 480TB.


Advantage of Dell Storage sc4020

Dell’s Fluid Data architecture migrates data through tiers dependent on access frequency. Up to three tiers are possible and a new feature is support for write-intensive SLC SSDs in the top tier and read-intensive MLC SSDs in the second tier.

Dell’s thinking here is that businesses can use fewer SSDs to get better performance than a big bank of SAS drives making flash-based storage more affordable. However, the choice is yours as tiers can be made up of any supported drive type.

Dell’s dynamic block architecture (DBA) does all the hard work as it uses metadata tables to keep track of all blocks. It maintains details such as the number of accesses, when it was written, which virtual volume it belongs to and so on.

DBA uses this information to determine which storage tier a data block should reside on and when to move it up or down the tiers. Consequently, a volume can contain data blocks that reside on different tiers dependent on their usage patterns.


We tested with two PowerEdge R720 servers running Windows Server 2012 R2 and equipped with QLogic dual-port 8Gbps FC adapters. With one server logged onto a virtual volume over a dual MPIO FC link, Iometer reported an impressive raw sequential read rate of 12.2Gb/sec.

Using a 4KB request size Iometer returned 160,000 and 90,000 IOPS for sequential and random read operations. Our random write test measured a steady 34,100 IOPS while our database test using a 66/34 per cent mix of random reads and writes came back with a speedy 36,000 IOPS.

With the second server in the mix, Iometer reported impressive cumulative rates of 318,000 and 170,000 IOPS for sequential and random reads. The random write test reported 60,000 IOPS while the database test on both servers saw a cumulative 52,000 IOPS.

Video of Dell Storage sc4020


The Storage SC4020 looks very affordable with a starting configuration comprising dual 8Gbps FC controllers and twelve 1TB NL SAS drives coming in at £19,300. It includes all the Fluid Data storage optimisation features in Dell’s SC8000 so it’s  easy to deploy and manage and we found performance to be impressive.

Technical Specification

Rack size3U
Controllers2 hot-swappable per chassis (active/active)
ProcessorsIntel® Xeon® Processor E5-2630 v3, 2.4GHz, 8 cores
Internal storage capacityInternal storage capacity
System memory128GB per SC5020 array (64GB per controller)
Supported expansion enclosuresDell SC420: 24 x 2.5” drive bays (12Gb SAS) Dell SC400: 12 x 3.5” drive bays (12Gb SAS)
Max raw capacity2PB per array (SSD or HDD), more in federated systems5
Storage mediaSAS and NL-SAS drives; different drive types, transfer rates, rotational speeds can be mixed in the same system. SSD: write-intensive and read-intensive drives HDD: 15K, 10K, 7.2K RPM
Front-end-network protocolsFC, iSCSI, SAS7 (supports simultaneous multiprotocol)
Back-end expansion protocols12Gb SAS
RAID supportRAID 0, 1, 5, 6, RAID 10, and RAID 10 DM (Dual Mirror); any combination of RAID levels can exist in single array
RAID tieringAuto-provisions and dynamically restripes multiple RAID levels on the same tier; no need to pre-allocate RAID groups
Data-at-rest encryptionSelf-encrypting drives (SEDs) in SSD or HDD formats Full Disk Encryption (FCE) based on AES-256 Drives certified to FIPS 140-2 Level 2 Key Management Server (KMS) options available for FIPS 140-2 Level 1, 2 and 3
Operating humidity ranges10% to 80% with 29°C (84.2°F) maximum dew point
ServicesDell ProSupport with deployment and consulting services. Optional ProSupport Plus is available offering proactive and preventative services to improve performance and stability. Dell Optimize is available for additional ongoing strategic counsel and guidance from a highly trained system analyst.
System sizingDell Performance Analysis Collection Kit (DPACK) tool
Drive warrantyAll SSDs and HDDs are warrantied for full lifetime wear-out replacement with valid service agreement. SSD warranty covers all formats: SLC, MLC and TLC
Operating temperature50 – 95°F (10 – 35°C)
Inlet typeNEMA 5-15/CS22.2, n°42
Amperage1485/100 – 14A, 1485/240 – 6.2A
Weight at max configuration24.22 kg (53.4 lb)






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