bcache tuning #10

  • By james-page
  • Latest version (#10)
  • xenial, bionic, cosmic
  • Stable

Description

Tune all bcache devices on a unit with best-practice
tuning options.


Overview

This charm performs best-practice performance tuning of bcache devices on
SD/NVMe based installations.

Cache Devices

Disable performance based congestion behaviour - the SSD or NVMe will in
all likelyhood always be faster than the underlying spindle:

congested_read_threshold_us: 0
congested_write_threshold_us: 0

Bcache Devices

Disable writethrough of sequential data writes:

sequential_cutoff: 0

Increase the amount of dirty data the cache device will hold before
starting to persist to the backing device:

writeback_percent: 30

Usage

To use this charm, simple deploy and relation to principle services:

juju deploy bcache-tuning
juju add-relation bcache-tuning ceph-osd
juju add-relation bcache-tuning nova-compute

This charm presents no configuration options.

Configuration

debug
(boolean) Enable debug logging.