On Thu, Jan 4, 2024 at 4:41 PM Peter <peter...@raksmart.com> wrote:
>
> I follow below document to setup image level rbd persistent cache,
> however I get error output while i using the command provide by the document.
> I have put my commands and descriptions below.
> Can anyone give some instructions? thanks in advance.
>
> https://docs.ceph.com/en/pacific/rbd/rbd-persistent-write-back-cache/
>
> https://access.redhat.com/documentation/en-us/red_hat_ceph_storage/5/html/block_device_guide/ceph-block-devices#enabling-persistent-write-log-cache_block
> [https://access.redhat.com/webassets/avalon/g/shadowman-200.png]<https://access.redhat.com/documentation/en-us/red_hat_ceph_storage/5/html/block_device_guide/ceph-block-devices#enabling-persistent-write-log-cache_block>
> Chapter 2. Ceph block devices Red Hat Ceph Storage 5 | Red Hat Customer
> Portal<https://access.redhat.com/documentation/en-us/red_hat_ceph_storage/5/html/block_device_guide/ceph-block-devices#enabling-persistent-write-log-cache_block>
> Access Red Hat’s knowledge, guidance, and support through your subscription.
> access.redhat.com
> I tried use host level client command, i got no error, however I won't be
> able to get cache usage output.
> "ceph config set client rbd_persistent_cache_mode ssd
> ceph config set client rbd_plugins pwl_cache"
>
>
>
> [root@master-node1 ceph]# rbd info sas-pool/testdrive
> rbd image 'testdrive':
> size 40 GiB in 10240 objects
> order 22 (4 MiB objects)
> snapshot_count: 0
> id: 3de76a7e7c519
> block_name_prefix: rbd_data.3de76a7e7c519
> format: 2
> features: layering, exclusive-lock, object-map, fast-diff,
> deep-flatten
> op_features:
> flags:
> create_timestamp: Thu Jun 29 02:03:41 2023
> access_timestamp: Thu Jun 29 07:19:40 2023
> modify_timestamp: Thu Jun 29 07:18:00 2023
>
> I check feature exclusive-lock has been already enabled
> and I run following command get fault output.
> [root@master-node1 ceph]# rbd config image set sas-pool/testdrive
> rbd_persistent_cache_mode ssd
> rbd: invalid config key: rbd_persistent_cache_mode
>
> [root@master-node1 ceph]# rbd config image set sas-pool/testdrive rbd_plugins
> pwl_cache
> rbd: invalid config key: rbd_plugins
Hi Peter,
What is the output of "rbd --version" on this node?
Were "ceph config set client rbd_persistent_cache_mode ssd" and "ceph
config set client rbd_plugins pwl_cache" above ran on a different node?
>
> root@node1:~# rbd status sas-pool/testdrive
> Watchers:
> watcher=10.1.254.51:0/1544956346 client.39553300
> cookie=140244238214096
>
>
> I hope to see the output include the persistent cache state like below:
>
> $ rbd status rbd/foo
> Watchers:
> watcher=10.10.0.102:0/1061883624 client.25496 cookie=140338056493088
> Persistent cache state:
> host: sceph9
> path: /mnt/nvme0/rbd-pwl.rbd.101e5824ad9a.pool
> size: 1 GiB
> mode: ssd
> stats_timestamp: Sun Apr 10 13:26:32 2022
> present: true empty: false clean: false
> allocated: 509 MiB
> cached: 501 MiB
> dirty: 338 MiB
> free: 515 MiB
> hits_full: 1450 / 61%
> hits_partial: 0 / 0%
> misses: 924
> hit_bytes: 192 MiB / 66%
> miss_bytes: 97 MiB
Normally, the output that you are expecting would be there only while
the image is opened.
Thanks,
Ilya
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