Support #51985
closedHelp-seeking for rbd persistent cache usage problems
100%
Description
The performance of the rbd persistent cache is tested. The fio is used to test the three modes of the ceph persistent write-back cache function: ssd, rwl, and disabled. The performance difference is similar. No file is generated in the rbd_persistent_cache_path directory.
Set the parameters as follows:
rbd_cache = true
rbd_cache_writethrough_until_flush = false
rbd_cache_size = 268435456
rbd_cache_max_dirty = 134217728
rbd cache target dirty = 33554432
rbd cache max dirty age = 5
debug_rbd=5/5
rbd_parent_cache_enabled = true
rbd plugins = parent_cache
rbd_cache_policy = writeback
rbd_cache_block_writes_upfront = true
rbd plugins = pwl_cache
rbd_persistent_cache_size =322122547200
rbd_persistent_cache_log_periodic_stats = true
rbd_persistent_cache_mode = ssd
rbd_persistent_cache_path = /mnt/rbd0
- Mount Options
#/dev/nvme1n1p1 on /mnt/rbd0 type xfs (rw, relatime, attr2, inode64, noquota)
rbd_persistent_cache_mode = rwl
rbd_persistent_cache_path = /mnt/ramcache
- Mount Options
xfs on /mnt/ramcache type ramfs (rw, relatime)
The logs are as follows:
2021-07-30T12:03:38.208+0800 7f110e30d700 5 librbd::PluginRegistry: 0x5627e0f7f7a0 init: attempting to load plugin: pwl_cache
2021-07-30T12:03:38.211+0800 7f110e30d700 5 librbd::plugin::WriteLogImageCache: 0x7f11000b2000 init:
You can see that WriteLogImageCache is initialized
Configure the disabled mode.
2021-07-30T12:55:51.547+0800 7faf9f7fe700 5 librbd::PluginRegistry: 0x565082e8c670 init: attempting to load plugin: pwl_cache
WriteLogImageCache is not initialized.
How to enable the rbd persistent cache function?
Files