Render Disks

by render-osse8f889396634MITListed Oct 8, 2026Updated Oct 8, 2026

Attaches and manages persistent disks on Render services—mount paths, sizing, snapshots, file transfers, and single-instance constraints. Use when the user needs persistent storage, file uploads, a custom database on disk, CMS media storage, or needs to understand why their service can't scale horizontally or use zero-downtime deploys. Trigger terms: persistent disk, disk, storage, mount path, sizeGB, SSD, file uploads, snapshots, disk restore, ephemeral filesystem.

Instructions onlyDevOps & Cloud
AI-generated overview

Guides attaching and managing persistent disks on Render services, covering mount paths, sizing, snapshots and constraints.

What it does
This skill provides instructions for attaching and managing persistent SSD disks on Render services, including mount path selection, size configuration, snapshots and file transfers. It documents critical constraints such as single-instance limits, disabled zero-downtime deploys, and runtime-only disk access. It also lists common patterns for CMS media storage, self-managed databases and stateful infrastructure, plus frequent mistakes and their fixes. A reference file covers sizing guidance, snapshot lifecycle and restore procedures.
When to use it
Use it when a user needs persistent storage on Render, such as file uploads, CMS media, or a self-managed database on disk. It also applies when explaining why a service cannot scale horizontally or use zero-downtime deploys, or when restoring data from a disk snapshot.
Requirements
Render paid web services, private services or background workers. No scripts are shipped; it is instructions only, with one reference document. SSH access is needed for SCP file transfers.

Render Persistent Disks

Persistent disks are high-performance SSDs you attach to a Render service to preserve filesystem changes across deploys and restarts. Without a disk, services have an ephemeral filesystem—all local file changes are lost on every deploy.

When to Use

  • Storing file uploads, CMS media, or user-generated content
  • Running a self-managed database (MySQL, MongoDB, ClickHouse) on Render
  • Deploying stateful infrastructure (Elasticsearch, Kafka, RabbitMQ, Mattermost)
  • Understanding why scaling is blocked or zero-downtime deploys are disabled
  • Restoring data from an automatic disk snapshot

For managed databases, prefer Render Postgres (render-postgres) or Key Value (render-keyvalue) over self-managed alternatives on disk.

Critical Constraints

These constraints affect architecture decisions. Understand them before attaching a disk:

ConstraintImpact
Single instance onlyCannot scale horizontally (numInstances must be 1, autoscaling not available)
No zero-downtime deploysOld instance stops before new instance starts (brief downtime on each deploy)
Runtime access onlyDisk is not available during buildCommand or preDeployCommand (those run on separate compute)
Not accessible from other servicesOnly the attached service can read/write the disk
Not available on cron jobsAttach to a web service, private service, or background worker instead
Not available on one-off jobsOne-off jobs run on separate compute without disk access
Can increase size, cannot decreaseStart small and grow as needed

Setup

Dashboard

  1. Go to your service's Disks page
  2. Set the mount path (absolute path where persistent data is stored)
  3. Choose a size in GB
  4. Click Add disk — triggers a new deploy

Blueprint

yaml
services:  - type: web    name: cms    runtime: node    plan: starter    region: oregon    buildCommand: npm ci && npm run build    startCommand: npm start    disk:      name: cms-data      mountPath: /var/data      sizeGB: 10

Mount Path

Only files written under the mount path are preserved. Everything else remains ephemeral.

RuntimeSource code pathExample mount path
Node.js, Python, Ruby, Elixir, Rust/opt/render/project/src/opt/render/project/src/uploads
Go/opt/render/project/go/src/github.com/<user>/<repo>.../data
DockerDockerfile's WORKDIR (commonly /app)/app/storage

Disallowed mount paths

Cannot mount at: /, /opt, /opt/render, /opt/render/project, /opt/render/project/src, /home, /home/render, /etc, /etc/secrets.

Subdirectories of these paths are fine (e.g. /opt/render/project/src/uploads).

Snapshots

  • Render creates an automatic snapshot every 24 hours
  • Snapshots are available for at least 7 days
  • Restore from the service's Disks page in the Dashboard
  • Full restore only — you cannot restore individual files
  • Destructive — all changes after the snapshot are lost

Do not restore snapshots for custom database recovery. Use database-native backup tools (mysqldump, mongodump) instead—disk snapshots may capture a corrupted database state.

File Transfers

SCP (via SSH)

bash
# Download from servicescp -s [email protected]_REGION.render.com:/mount/path/file ./local-file
# Upload to servicescp -s ./local-file [email protected]_REGION.render.com:/mount/path/file

Requires SSH access enabled for the service.

Magic-Wormhole

Available on all native runtimes (install manually on Docker):

bash
# On the service shellwormhole send /mount/path/file
# On your local machinewormhole receive

Common Patterns

PatternService typeMount pathNotes
WordPress / Ghost / CMSWeb Service/var/data or /app/contentMedia uploads, SQLite
Self-managed MySQLPrivate Service/var/lib/mysqlUse mysqldump for backups, not disk snapshots
File upload APIWeb Service/opt/render/project/src/uploadsSingle instance constraint
ElasticsearchPrivate Service/usr/share/elasticsearch/dataStateful search infrastructure

Common Mistakes

MistakeFix
Expecting horizontal scaling with a diskNot possible — disk services are single-instance only
Mounting at a disallowed pathUse a subdirectory (e.g. /opt/render/project/src/uploads not /opt/render/project/src)
Reading disk during build or pre-deployThese run on separate compute — move logic to the start command
Restoring disk snapshot for a databaseUse database-native backups instead
Starting with a large disk sizeStart small — you can increase but never decrease

References

DocumentContents
references/sizing-and-snapshots.mdSizing guidance, snapshot lifecycle, restore procedures, cost patterns

Related Skills

  • render-web-services — Deploy lifecycle, health checks (disk disables zero-downtime)
  • render-private-services — Internal services with disks (Elasticsearch, MySQL)
  • render-blueprints — disk field reference in render.yaml
  • render-postgres — Managed database alternative (no disk management needed)

Source and attribution

Source:render-oss/render-plugin-claude-codeinskills/render-disksat commite8f8893

License: MIT

Content belongs to its original authors. SourceWeft indexes it from a public repository.

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