meta data for this page
  •  

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Next revision		Previous revision
linux:fs:ssd_cache [2021/02/16 21:20] – created niziaklinux:fs:ssd_cache [2022/02/15 07:42] (current) – niziak
Line 1: Line 1:
-====== SSD caching ======+====== HDD on SSD caching ======
  
 Speed up HDDs with additional SSD/NVMe caching. Speed up HDDs with additional SSD/NVMe caching.
Line 7: Line 7:
     * 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]]