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Dell DCA-ISM study materials
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Dell DCA-ISM: Cloud Computing and Cloud Storage

Dell DCA-ISM · Work through your exam, one topic at a time.

All guide sections

Cloud Computing and Cloud Storage

Cloud questions test NIST vocabulary, which workload suits which service and deployment model, and the cost and latency traps that appear once data starts moving.

NIST essentials

  • Five characteristics: on-demand self-service, broad network access, resource pooling, rapid elasticity and measured service.
  • Service models: IaaS supplies virtual machines, networks and block volumes; PaaS supplies a managed runtime and storage APIs; SaaS supplies the application. The customer's responsibility shrinks as you move up.
  • Deployment models: private, public, hybrid and community. Hybrid means orchestration and portability between private and public, not simply owning two environments.

Cloud storage options and Dell positioning

  • Object storage with an S3-compatible API is the default for cloud-native data (ECS, APEX object services). Block volumes attach to instances; file shares are served over NFS or SMB by PowerScale, Azure Files or EFS.
  • Tiering and gateways move cold data to cloud object storage while the namespace stays on-premises: PowerScale CloudPools, PowerProtect DD Cloud Tier, and APEX Block or File Storage Services for lift-and-shift into AWS or Azure.
  • Consumption models: APEX as-a-service and Flex On Demand, where you pay for buffer capacity only as you use it. DR to cloud is delivered by PowerProtect Data Manager and Cyber Recovery, or RecoverPoint for VMs to AWS or Azure.

Cost and architecture realities

  • Egress charges, per-operation GET and PUT costs, and retrieval fees on cold storage classes frequently exceed the storage line item.
  • Data gravity and round-trip latency make lift-and-shift of latency-sensitive databases a poor fit; elasticity (automatic scale with demand) is not the same as scalability (ability to grow).

Worked example

A 500 TB dataset has a 20% active working set, so 400 TB is tiered to object storage at 0.012 USD per GB-month: 400,000 GB times 0.012 equals 4,800 USD per month. If analytics recall 10% of cold data monthly and egress is 0.09 USD per GB, that is 40,000 GB times 0.09, or 3,600 USD, adding 75% to the storage bill. Recalling 30% would cost 10,800 USD, more than the storage itself, so working-set analysis must precede the tiering decision.

Traps that cost marks

  • Assuming cloud shifts DR responsibility to the provider; you still own RPO, RTO and testing.
  • Ignoring egress and per-operation pricing in TCO comparisons.
  • Describing hybrid cloud as any environment using two platforms without orchestration.