Block storage divides data into fixed-size blocks and presents them to a server as a raw disk volume, which the operating system formats with a file system.
Why it matters
It offers low latency and supports small random reads and writes, so it is the usual choice for databases, boot disks and applications that need a normal file system.
Volumes are normally attached to one server at a time and live in a single zone. They are more expensive per gigabyte than object storage and need snapshots or backups for protection.
Example
You create a 200 GB volume in the cloud console, attach it to a VM as /dev/vdb, then run mkfs.ext4 /dev/vdb and mount it at /var/lib/postgresql. The database now stores its files there.
Common mistakes
- Assuming the volume is backed up automatically.
- Resizing the volume but forgetting to extend the file system.
- Choosing block storage for large static files that object storage would hold more cheaply.
Related
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