No, `zpool trim` does not have an effect on cache devices, if I recall correctly. Cache devices are trimmed fully upon addition to a pool with `zpool add` if the module parameter `l2arc_trim_ahead` is greater than 0.
To clear the cache device you would have to `zpool remove` and then `zpool add` the cache device. On Wed, Oct 21, 2020 at 5:49 PM Mai Ling <mailinglist...@gmail.com> wrote: > >the outdated L2ARC data will NOT be served > > but is it cleared with `zpool trim`? > > On 10/20/20, Georgios Amanakis <gamana...@gmail.com> wrote: > > Yes, this is expected behaviour. L2ARC does not invalidate previously > > written data on cache devices even if they are removed from the pool. > > > > You do not need to worry though, the outdated L2ARC data will NOT be > > served, as their checksum, DVA properties, and birth transaction will > > differ from the data present in the disks of the pool. > > > > On Tue, Oct 20, 2020, 6:03 PM <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> > >> > > > > ------------------------------------------ > > openzfs: openzfs-developer > > Permalink: > > https://openzfs.topicbox.com/groups/developer/T77c79c75ab05a912-Mb34a9323a370dcef95a2d53f > > Delivery options: > > https://openzfs.topicbox.com/groups/developer/subscription > > ------------------------------------------ openzfs: openzfs-developer Permalink: https://openzfs.topicbox.com/groups/developer/T77c79c75ab05a912-M2c35192f96407a566d2f1376 Delivery options: https://openzfs.topicbox.com/groups/developer/subscription
