blog/content/ceph-benchmarking/index.md

+++ title = "Ceph Benchmarking" date = 2026-03-01 description = "The results of some of my recent ceph benchmarks" draft = true

[taxonomies] categories = ["Homelab"] tags = ["Homelab", "Ceph"] +++

Setup everything for the Benchmarking

On a machine in the ceph-cluster already:

1. Generate a minimal ceph config using ceph config generate-minimal-conf
2. Create a user for Benchmarking
   1. Create a new user ceph auth add client.linux_pc
   2. Edit the caps for my use-case
      • mgr: profile rbd pool=test-rbd
      • mon: profile rbd
      • osd: profile rbd pool=test-rbd
   3. Get the keyring configuration using ceph auth get client.linux_pc

On the client machine doing the Benchmarking:

1. Install basic ceph tools apt-get install -y ceph-common
2. Load the rbd kernel module modprobe rbd
3. Setup local ceph config
   • Copy the generated configuration to /etc/ceph/ceph.conf
   • chmod 644 /etc/ceph/ceph.conf
4. Setup local ceph keyring
   • Copy the keyring configuratio nto /etc/ceph/ceph.client.linux_pc.keyring
   • chmod 644 /etc/ceph/ceph.client.linux_pc.keyring
5. Confirm your configuration is working by running ceph -s -n client.linux_pc

Setup the benchmark itself:

1. rbd create -n client.linux_pc --size 10G --pool test-rbd bench-volume
2. rbd -n client.linux_pc device map --pool test-rbd bench-volume (which should create a new block device, likely /dev/rbd0)
3. mkfs.ext4 /dev/rbd0
4. mkdir /mnt/bench
5. mount /dev/rbd0 /mnt/bench

Benchmarks

Results

{% details(summary="Random Reads - 1 Job") %} {{ fio_benchmark(path="content/ceph-benchmarking/benchmarks/random_read.json") }} {% end %}

{% details(summary="Random Writes - 1 Job") %} {{ fio_benchmark(path="content/ceph-benchmarking/benchmarks/random_write.json") }} {% end %}

{% details(summary="Sequential Reads - 1 Job") %} {{ fio_benchmark(path="content/ceph-benchmarking/benchmarks/seq_read.json") }} {% end %}

{% details(summary="Sequential Writes - 1 Job") %} {{ fio_benchmark(path="content/ceph-benchmarking/benchmarks/seq_write.json") }} {% end %}

TODO

• Try directly on the block device
• Try this using xfs instead of ext4
• Try this with and without drive caches

Details

{% details(summary="Command to convert raw data into vis data") %}

jq '[.jobs[] | { iodepth: ."job options".iodepth, bs: ."job options".bs, operations: { iops: .write.iops, bw_bytes: .write.bw_bytes } }]' content/ceph-benchmarking/benchmarks/raw_random_write.json | jq '
  # collect sorted unique labels
  (map({key:.bs,value:1})|from_entries|keys_unsorted) as $labels
  |
  {
    labels: $labels,
    iodepths:
      (
        group_by(.iodepth)
        | map(
            . as $group
            | {
                iodepth: ($group[0].iodepth | tonumber),
                iops: [
                  $labels[] as $l
                  | ($group[] | select(.bs == $l) | .operations.iops) // null
                ],
                bw: [
                  $labels[] as $l
                  | ($group[] | select(.bs == $l) | .operations.bw_bytes) // null
                ]
              }
          )
      )
  }
'

{% end %}