Storage, Networking, and Data Services
Domain 3 - Storage, Networking, and Data Services. This domain tests matching data access patterns to IBM Cloud storage and databases, and building secure VPC connectivity.
Storage and data
- Block Storage for VPC is zonal, low-latency, and attached to one virtual server; use it for OS volumes and databases needing block devices.
- File Storage for VPC provides shared NFS file shares across instances in a zone; use it for shared application content.
- IBM Cloud Object Storage is S3-compatible and HTTP-accessed, for unstructured data, backups, archives, and static assets; storage classes trade retrieval cost and latency.
- Managed databases such as IBM Cloud Databases, Db2 on Cloud, Db2 Warehouse, and watsonx.data offload backup, patching, and scaling; choose by engine, consistency, and analytics needs.
Networking
A VPC is regional; subnets are zonal. Security groups are stateful instance-level firewalls; network ACLs are stateless subnet-level filters. Public gateways give a subnet outbound internet; floating IPs expose one instance; load balancers distribute traffic. Direct Link provides private dedicated connectivity; Transit Gateway connects VPCs, classic infrastructure, and Direct Link. DNS Services provides private and public zones.
Worked example
A web tier serves images globally and writes logs. Object Storage fits images and logs because access is HTTP and durability is high. A database on the same VPC needs low-latency block storage, not object storage. For private connectivity to on-premises, combine Direct Link with Transit Gateway rather than exposing the database through a public gateway.
Traps
Object Storage cannot be mounted as a local disk; security groups are stateful while ACLs are stateless; a public gateway is not a load balancer; and Direct Link does not replace application security by itself.