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Requirements

Software

Check out the prerequisites section to get started.

Minimum Requirements for Ceph Storage node

RAM

  • 16 GB baseline, plus 5 GB for every OSD on the node

Network

  • For High-performance, high-endurance enterprise NVMe SSDs:
    • 10 Gigabit Ethernet (GbE) per 2 OSDs.
  • For HDDs:
    • 10 GbE per 12 OSDs each for client- and cluster-facing networks.

CPU

  • 1 core per HDD OSD minimum

For IOPS optimized solutions where there are NVMe SSDs

  • 6 cores per NVMe SSD

Block.db sizing for OSD

The general recommendation is to have block.db size in between 1% to 4% of block size. For RGW workloads, it is recommended that the block.db size isn’t smaller than 4% of block, because RGW heavily uses it to store metadata (omap keys). For example, if the block size is 1TB, then block.db shouldn’t be less than 40GB. For RBD workloads, 1% to 2% of block size is usually enough.

Block.wal sizing

If there is only a small amount of fast storage available (e.g., less than a gigabyte), we recommend using it as a WAL device. If there is more, provisioning a DB device makes more sense. The BlueStore journal will always be placed on the fastest device available, so using a DB device will provide the same benefit that the WAL device would while also allowing additional metadata to be stored there (if it will fit). This means that if a DB device is specified but an explicit WAL device is not, the WAL will be implicitly colocated with the DB on the faster device.

When not using a mix of fast and slow devices, it isn’t required to create separate logical volumes for block.db (or block.wal). BlueStore will automatically colocate these within the space of block.

Partition Layout

Either a separate /var partition or the OS Root partition should be at least 100 GB for MON nodes.

OS Disk:

  • At least 100-200GB in total size
  • SATA SSD or NVMe SSD.

Recommended layout:

  • / - 20GB
  • /var - 75-100GB or more
  • /var/lib/containers - (this assumes CRI-O is used) 75-100GB
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