Installation questions

What are the minimum system and operating system requirements to install IBM Storage Ceph?

Red Hat Enterprise Linux (RHEL) on AMD64 or Intel64 systems is required. Only specific RHEL versions are supported. Ensure that networking, root-level access, and a sufficient number of systems or nodes are available before installation.

How many nodes are needed for a basic production cluster?

A basic production IBM Storage Ceph cluster requires a minimum of three nodes when using SSD-based OSDs or four nodes when using HDD-based OSDs. The minimum can vary depending on workload type, failure-domain requirements, and licensing constraints. For most production environments, four nodes are recommended to provide improved resiliency and operational flexibility.

For more information, see IBM Storage Ceph Supported Configuration on IBM Support.

What is the difference between using cephadm and cephadm-ansible or other deployment tools?

cephadm is the IBM-recommended orchestration tool for deploying and managing containerized Ceph daemons. The cephadm-ansible utility provides Ansible modules for automation but is not an orchestrator. cephadm-ansible should not be confused with the deprecated ceph-ansible suite, which is obsolete and not supported with current releases.

How do I register systems and obtain subscriptions or entitlements?

Register systems with Red Hat Subscription Management, enable the required RHEL repositories, and configure the IBM Storage Ceph repositories. Ensure that valid IBM entitlements and licenses are available before installation.

Is a trial or evaluation edition available?

Yes. A 60-day free trial is available for the Pro Edition.

What are Day 1 and Day 2 operations?

Day 1 operations include bootstrapping and installing the initial cluster components such as Monitors, Managers, and OSDs. Day 2 operations include expanding the cluster by adding OSDs, gateways, and metadata servers.

How do I configure networking, firewalls, and required ports?

Ensure that the default Ceph ports are accessible, SSH access is available for cephadm, and network latency, bandwidth, routing, and DNS are configured correctly. For more information, see Configuring Ceph network configuration.

How do I size OSDs, storage devices, and raw capacity?

Sizing depends on whether HDDs or SSDs are used and on performance and redundancy requirements. Licensing is based on raw capacity before replication or erasure coding. For more information, see IBM Storage Ceph Supported Configuration document.

How do I bootstrap the storage cluster?

Use cephadm to bootstrap the cluster, which initializes the monitor, manager, and initial OSDs. For more information, see Bootstrapping a new storage cluster.

What licensing options and editions are available?

IBM Storage Ceph is available in Pro and Premium editions. The Premium edition includes RHEL subscriptions, while the Pro edition requires you to bring your own. Licenses are available as perpetual, monthly, or annual subscriptions.

I bootstrapped Ceph but cannot access the dashboard. What should I check?

Verify that the Ceph Manager dashboard module is enabled, firewall rules allow access to TCP port 8443, and TLS certificates are configured correctly.

I have only two servers. Can I still run Ceph for testing?

Yes, but this configuration is supported only for testing and evaluation, not for production. For more information, see IBM Storage Ceph Supported Configuration document.

The bootstrap command fails because the container image cannot be found. What should I do?

Ensure that the IBM Storage Ceph repositories are enabled, entitlements are valid, and container tooling can access the registry. In air-gapped environments, verify proxy and mirror configuration. For more information, see Disconnected (air-gapped) installation.

What should I do if I want to add OSDs but cephadm does not detect new disks?

Ensure that new devices are unused and fully wiped. Verify available devices by using the ceph orch device ls command and zap disks if required. Device filters should account for base-10 and base-2 capacity differences when specifying size ranges.

What should I check if networking is configured but latency is high during installation?

Ceph is sensitive to latency. Ensure sufficient bandwidth, consider a dedicated backend network, and use bonded links where possible. Jumbo frames (MTU 9000) are recommended. Validate balanced traffic distribution with tools such as iptraf.

What should I do if the bootstrap node succeeded but adding hosts fails?

Verify that cephadm has distributed SSH keys correctly and that passwordless SSH access from the bootstrap node to all hosts is working.

Can I install IBM Storage Ceph on mixed hardware (SSD and HDD)?

Yes. A common configuration uses SSDs, preferably NVMe, for WAL and DB and HDDs for data. Device classes and CRUSH rules can be used to control placement. In most cases, WAL and DB devices should be sized to at least 2.5% of the main data device.

How do I preconfigure erasure coding profiles during installation?

Create erasure coding profiles after the cluster is installed by using the ceph osd erasure-code-profile set command. Plan profiles carefully, because changes after data placement require data migration.

What happens if bootstrap fails midway?

Clean up containers, reset the cephadm state, remove configuration files, and restart the bootstrap process.