In MAAS, bcache is a Linux kernel block layer cache that combines the speed of solid-state drives (SSDs) with the capacity of traditional hard disk drives (HDDs). By configuring bcache, MAAS enhances storage performance during machine deployments.
Key bcache components in MAAS
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bcache: Represents a bcache device on a machine.
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bcaches: Manages multiple bcache devices on a machine.
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bcache-cache-set: Manages a specific bcache cache set on a machine.
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bcache-cache-sets: Oversees all bcache cache sets on a machine.
MAAS storage layouts incorporating bcache
MAAS offers various storage layouts, including a bcache layout designed to boost disk performance. In this configuration, the boot disk serves as the backing device, while an SSD functions as the cache. The bcache device is formatted with the ext4 filesystem and mounted at the root (/). If no SSDs are tagged appropriately, MAAS defaults to a flat layout.
Customizing bcache in MAAS
Users can tailor the bcache setup by specifying options such as:
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cache_device: Determines the block device used as the cache, defaulting to the smallest SSD.
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cache_mode: Sets the caching strategy, with ‘writethrough’ as the default.
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cache_size: Defines the partition size on the cache device, defaulting to 100%.
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cache_no_part: Indicates whether to create a partition on the cache device, defaulting to false.
These configurations allow for optimized storage performance tailored to specific deployment needs.
Implementing bcache via MAAS CLI
To configure bcache using the MAAS CLI, users can define a storage layout that specifies devices for both cache and storage. Both can be either partitions or entire disks. Additionally, the cache mode can be set to control the caching behavior.
By leveraging these bcache functionalities, MAAS users can significantly enhance storage performance, ensuring efficient and rapid machine deployments.
Last updated 2 days ago.