Unfortunately yes. Persistent L2ARC log refers all L2ARC writes, but it does nothing for evictions. So while the system is running, the L2ARC headers are evicted from ARC on delete, but after L2ARC is re-imported they are all reconstructed, wasting resources until the respective L2ARC blocks get overwritten with new data.
I've brought it up with the developer during the recent OpenZFS DevSummit. On 20.10.2020 06:52, adam.blaszczykow...@gmail.com wrote: > Hello, > I have noticed unusual behaviour with Persistent L2ARC . I will try to > describe how to reproduce this problem. > All tests are performed on zfs-2.0.0-rc1_71_g51de0fc. I am using Virtual > Machine on ESXi 6.7 server. > > Test scenario: > 1. ZFS pool created with L2ARC that has about 8,4 GB of data on L2arc disk > 2. Disconnecting VM disk with L2ARC from Virtual Machine > 3. Deleting some data from the zpool with disconnected L2ARC disk > - zpool iostat command shows that some of cached data also has been > removed from disconnected L2ARC disk > 4. Reconnecting VM disk with L2ARC disk to Virtual Machine and rebooting > system > 5. Adding new data to the zpool - new data are cached in L2ARC disk > 6. Deleting all data from zpool > 7. L2arc disk still has some data, even if there is no data on zpool > 8. Rebooting system > 9. After reboot the same situation, zpool is empty but L2ARC disk still > has some data > > I am expecting that deleting all data from zpool also removes data from > L2ARC cache. > Is it normal behaviour of Persistent L2ARC? > > Thank you > *openzfs <https://openzfs.topicbox.com/latest>* / openzfs-developer / > see discussions <https://openzfs.topicbox.com/groups/developer> + > participants <https://openzfs.topicbox.com/groups/developer/members> + > delivery options > <https://openzfs.topicbox.com/groups/developer/subscription> Permalink > <https://openzfs.topicbox.com/groups/developer/T77c79c75ab05a912-Me6344594a06ca2007e812e93> > -- Alexander Motin ------------------------------------------ openzfs: openzfs-developer Permalink: https://openzfs.topicbox.com/groups/developer/T77c79c75ab05a912-M0752ca407e621b92f0884798 Delivery options: https://openzfs.topicbox.com/groups/developer/subscription
