55 lines
2 KiB
Markdown
55 lines
2 KiB
Markdown
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## Disk based caching
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Disk caching can be turned on by updating the "cache" config
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settings for minio server. By default, this is at `${HOME}/.minio`.
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"cache" takes the drives location, duration to expiry (in days) and any
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wildcard patterns to exclude certain content from cache as
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configuration settings.
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```
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"cache": {
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"drives": ["/path/drive1", "/path/drive2", "/path/drive3"],
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"expiry": 30,
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"exclude": ["*.png","bucket1/a/b","bucket2/*"]
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},
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```
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The cache settings can also be set by the environment variables
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below. When set, environment variables override any cache settings in config.json
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```
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export MINIO_CACHE_DRIVES="/drive1;/drive2;/drive3"
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export MINIO_CACHE_EXPIRY=90
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export MINIO_CACHE_EXCLUDE="pattern1;pattern2;pattern3"
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```
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- Cache size is 80% of drive capacity. Disk caching requires
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Atime support to be enabled on the cache drive.
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- Expiration of entries takes user provided expiry as a hint,
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and defaults to 90 days if not provided.
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- Garbage collection sweep of the expired entries happens whenever
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disk usage is > 80% of drive capacity until sufficient disk
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space has been freed.
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- Object is cached only when drive has sufficient disk space for 100 times the size of current object
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### Behavior
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Disk caching happens on both GET and PUT operations.
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- GET caches new objects for entries not found in cache.
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Otherwise serves from the cache.
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- PUT/POST caches all successfully uploaded objects. Replaces
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existing cached entry for the same object if needed.
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When an object is deleted, it is automatically cleared from the cache.
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NOTE: Expiration happens automatically based on the configured
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interval as explained above, frequently accessed objects stay
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alive in cache for a significantly longer time on every cache hit.
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The following caveats apply for offline mode
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- GET, LIST and HEAD operations will be served from the disk cache.
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- PUT operations are disallowed when gateway backend is offline.
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- Anonymous operations are not implemented as of now.
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