I plan to create ZFS pool with cache option:

zpool create .. raidz1 /dev/... cache sdX1

and then ZFS with -V (-V means block device will be created)

zfs create -o compression=off -o dedup=off -V 13....

Question: ZFS cache device affects performance in case of creating block device?

My OS: debian 9.5

Thanks in advance.

  • 1
    The cache device works for volumes as well as datasets if that's the question. If the addition if a cache device translates to a performance advantage for your particular use case that's a different question and can't be answered with the information provided.
    – Marco
    Jan 14, 2019 at 15:02
  • by volumes you talking about block devices (created with -V option)?
    – iNio
    Jan 14, 2019 at 18:52
  • Yes, called volumes or zvols.
    – Marco
    Jan 14, 2019 at 19:20

1 Answer 1


L2ARC works for both datasets and volumes. Truth to be tell, ZVOLs are little more that "hidden" files with some specific block abstraction - and they sit atop of the DMU (just as regular datasets with regular ZPL).

That said, it is not possible to predict if and how much the additional L2ARC will benefit your workload.

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