SysPad › Lessons › storage lessons › EBS Volume
How EBS Volume works
Network-attached block storage for a single EC2 instance. Capped by BOTH provisioned IOPS and MB/s - small random I/O hits the IOPS wall, large sequential I/O hits the throughput wall. gp3 decouples IOPS from size.
EBS is the hard drive for your EC2 instance, except it’s attached over the network and lives a life of its own. It behaves like a local disk (you format it, mount it, the OS sees blocks), but it persists independently of the instance and can be backed up, resized, and restored. The catches: it belongs to one instance, in one AZ.
What you will learn
- What is "block storage", and how does EBS differ from S3 and EFS?
- Why does an EBS volume survive its instance, and where is it pinned?
- How do volume types trade IOPS, throughput, and cost?
- What do snapshots give you?
A disk for one instance
EBS provides block storage: raw volumes the operating system treats like a physical disk (partition, format, mount). A volume attaches to a single EC2 instance at a time and is the natural home for an OS, a database’s files, or anything needing low-latency random read/write. (A niche exception, Multi-Attach on io1/io2, lets a few same-AZ instances share one volume with a cluster-aware filesystem.)
Persistent, but AZ-bound
A volume’s lifecycle is separate from the instance: stop or terminate the instance (if not set to delete-on-termination) and the volume keeps your data. But an EBS volume lives in a single Availability Zone, you can only attach it to instances in that same AZ.
Volume types
EBS offers types for different needs: gp3 (general-purpose SSD, balanced, provisionable IOPS/throughput), io2 (high-performance SSD for demanding databases), and HDD types st1 (throughput-optimised) and sc1 (cold, cheapest) for big sequential workloads.
⚓ gp3 for most workloads; io2 for IOPS-hungry databases; st1/sc1 for large logs/big-data scans.
Snapshots
A snapshot is a point-in-time backup of a volume stored in S3, taken incrementally (only changed blocks after the first). From a snapshot you restore a volume, copy it to other AZs/regions, or stamp out many identical volumes.
Flashcards
- What kind of storage is EBS, and who can use one volume?
- Block storage (a disk to the OS), attached to one EC2 instance at a time, ideal for OS disks and database files.
- Does an EBS volume die with its instance?
- No (unless delete-on-termination is set), it persists independently and can be reattached, within the same AZ.
- How do you get an EBS volume’s data into another AZ or region?
- Take a snapshot (to S3) and create a new volume from it in the target AZ/region, volumes themselves are AZ-bound.
- gp3 vs io2 vs st1/sc1?
- gp3 = balanced general SSD; io2 = high-IOPS SSD for demanding DBs; st1/sc1 = throughput/cold HDD for big sequential data.
- What is an EBS snapshot and where does it live?
- A point-in-time, incremental backup of a volume stored in S3; used to restore or copy volumes across AZs/regions.
Sources
Open the SysPad canvas · Official EBS Volume documentation