Setting up the storage-class memory device driver

Red Hat Enterprise Linux 9.2 LPAR mode

Configure the storage-class memory device driver by using the module parameters.

Storage-class memory module parameter syntax

Read syntax diagramSkip visual syntax diagram modprobe scm_block  nr_requests=64 nr_requests= <num>  write_cluster_size=64 write_cluster_size= <num>  nr_request_per_io=8 nr_request_per_io= <num>
where
nr_requests
specifies the number of parallel I/O requests. Set this number to the number of EADM subchannels. The default is 64.
write_cluster_size
specifies the number of pages that are used by the read-modify-write algorithm (available if CONFIG_SCM_BLOCK_CLUSTER_WRITE=y). The default is 64, resulting in all write requests smaller than 256 KiB being translated to 256 KiB writes. 1 KiB is 1024 bytes. Valid values are 2, 4, 8, 16, 32, 64, and 128. Do not change this value unless asked to do so by your service organization.
nr_request_per_io
submits more concurrent I/O requests than the current limit, which is based on the number of available EADM subchannels (64). Valid values are 1 - 64. Increasing the requests increases the number of I/O requests per second, especially for requests with a small block size. The default number of requests is 8. Depending on the workload, this setting might improve the throughput of the scm_block driver.