Overrides for the kernel zlib

Use the dfltcc= kernel parameter to override the defaults for the kernel zlib.

Red Hat Enterprise Linux 8.6 LPAR mode z/VM guest KVM guest

Format

Figure 1. dfltcc= syntax

on: enables on-chip acceleration for compression level 1 and for decompression. This is the default.
off: turns off on-chip acceleration for both compression and decompression.
def_only: enables on-chip acceleration for compression on level 1 but not for decompression.
inf_only: enables on-chip acceleration for decompression only.
always: enables on-chip acceleration for decompression and for compression regardless of the requested compression level.
Note: On-chip compression with the Integrated Accelerator for zEDC is approximately equivalent to compression level 1. Forcing On-chip compression for software that requests a higher compression level can result in a larger compressed data volume than intended by the author of the software.

dfltcc=inf_only