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linux:fs:ssd_cache [2021/02/16 21:20] niziak created |
linux:fs:ssd_cache [2022/02/15 07:42] (current) niziak |
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| - | ====== SSD caching ====== | + | ====== HDD on SSD caching ====== |
| Speed up HDDs with additional SSD/NVMe caching. | Speed up HDDs with additional SSD/NVMe caching. | ||
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| * it is possible to add ''cache'' and ''log'' devices to ZFS pool. ''Log'' is a journal for synchronous writes. | * it is possible to add ''cache'' and ''log'' devices to ZFS pool. ''Log'' is a journal for synchronous writes. | ||
| * LVM DM-Cache | * LVM DM-Cache | ||
| + | * No HDD reformating if it is already using LVM | ||
| * it is possible to add cache device to logical volume: [[https://www.redhat.com/en/blog/improving-read-performance-dm-cache|Improving read performance with dm-cache]] | * it is possible to add cache device to logical volume: [[https://www.redhat.com/en/blog/improving-read-performance-dm-cache|Improving read performance with dm-cache]] | ||
| + | * [[https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/logical_volume_manager_administration/lvm_cache_volume_creation]] | ||
| * It is hot-spot cache, to cache only frequently accessed data, so simple copy of big file doesn't fill cache. | * It is hot-spot cache, to cache only frequently accessed data, so simple copy of big file doesn't fill cache. | ||
| * Write cache is also possible: https://man.archlinux.org/man/lvmcache.7 | * Write cache is also possible: https://man.archlinux.org/man/lvmcache.7 | ||
| + | * [[https://wiki.archlinux.org/index.php/bcache|bcache]] | ||
| + | * need to reformat HDD | ||
| + | Writeback caching: | ||
| + | * Filesystem corruption when SSD cache fails. Possible workaround for mirroring FS is to use 2 separate caching devices for 2 mechanical drives. | ||
| + | |||
| + | Benchmarks: | ||
| + | * [[http://strugglers.net/~andy/blog/2017/07/19/bcache-and-lvmcache/|bcache and lvmcache]] | ||
| + | |||
| + | |||
| + | ===== flashcache ===== | ||
| + | |||
| + | <code bash> | ||
| + | apt-get install flashcache-dkms flashcache-utils | ||
| + | </code> | ||
| + | |||
| + | Reference [[https://wiki.archlinux.org/index.php/flashcache]] | ||