Google Cloud Storage

When you store files on a server's local disk, you run out of space quickly, and replacing the server means losing files. Sharing the same files across multiple servers is also cumbersome.

Before object storage, organizations managed NAS or SAN systems in their data centers. Upgrading capacity meant buying new hardware and scheduling downtime to migrate data. Backup windows grew longer as data volumes increased — eventually exceeding overnight hours and eating into business time. Sharing files across geographic offices required expensive WAN replication setups that were fragile and slow to synchronize. As web applications and mobile apps generated more unstructured data — images, logs, user uploads — those on-premises systems couldn't scale fast enough. Object storage emerged as a model where capacity is effectively unlimited and replication is handled automatically, eliminating the hardware procurement and maintenance cycle.

When you upload a file, Cloud Storage writes it as an object into a bucket and automatically replicates it across multiple zones in the region. From that point, any service can read the object over HTTP — there's no filesystem mount, so there's no limit on how many clients can access the same file simultaneously. Lifecycle policies run periodically, checking each object's age and access patterns. When an object crosses a threshold you define — say, 30 days without access — the policy transitions it to a cheaper storage class like Nearline or Coldline. Objects that age past a longer threshold can be deleted automatically. This keeps storage costs in line without manual intervention.

Cloud Storage and Persistent Disk both store data but are accessed differently. Persistent Disk is block storage — raw disk volumes that a VM reads sector by sector, like a local hard drive. A Persistent Disk is mounted to a single VM (or a small number of VMs with read-only access) and provides the low-latency random I/O that databases and operating systems need. Cloud Storage is an object store accessed via HTTP API. If you need to read and write data over HTTP without filesystem mounts — and allow any number of services to access files simultaneously — Cloud Storage is the right choice. If you need a disk volume that a VM treats as its own local storage, use Persistent Disk.

Ideal for static web assets, user uploads, logs, backups, and data lakes where files need to be stored in bulk and read by multiple services. Not suitable when you need disk volumes directly mounted to a VM.