Lustre 1.6 Operations Manual

22.3.6 Changing Parameters
You can set the following parameters at the mkfs time, on a non-running target disk,
via tunefs.lustre or via a live MGS using lctl.
With mkfs.lustre
While you are using the mkfs command and creating the filesystem, you can add
parameters with the --param option:
$ mkfs.lustre --mdt --param="sys.timeout=50" /dev/sda
With tunefs.lustre
If a server is stopped, you can add the parameters via tunefs.lustre with the
same --param option:
$ tunefs.lustre --param="failover.node=192.168.0.13@tcp0" /dev/sda
With tunefs.lustre, parameters are "additive" -- to erase all old parameters and just
use the newly-specified parameters, use tunefs.lustre --erase-params --
param=....
With lctl
While a server is running, you can change many parameters via lctl conf_param:
$ mgs> lctl conf_param testfs-MDT0000.sys.timeout=40
$ anynode> cat /proc/sys/lustre/timeout
Note – The lctl conf_param command permanently sets parameters in the
filesystem configuration.
22-8 Lustre 1.6 Operations Manual • September 2008