Lustre 1.6 Operations Manual

4.2.3.2 Running the Writeconf Command
To run writeconf, first remove all existing configuration files for a filesystem. Use
the writeconf command on an MDT to erase all the configuration logs for the
filesystem. The logs are regenerated only as servers restart; therefore all servers must
be restarted before clients can access filesystem data. The logs are regenerated as in
a new filesystem; old settings from lctl conf_param are lost, and current server NIDs
are used. Only use the writeconf command if:
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The configuration logs are into a state where the filesystem cannot start; or
You are changing the NIDs of one of the servers.
To run the writeconf command:
1. Unmount all the clients and servers.
2. With every server disk, run:
$ mdt> tunefs.lustre --writeconf /dev/sda1
3. Remount all servers. You must mount the MDT first.
Caution – Running the writeconf command on the MDS will erase all pools
information (as well as any other parameters set via lctl conf_param). We
recommend that the pools definitions (and conf_param settings) be executed via a
script, so they can be reproduced easily after a writeconf is performed.
4.2.3.3 Changing a Server NID
To change a server NID:
1. Update the LNET configuration in /etc/modprobe.conf so the lctl list_nids is
correct.
2. Regenerate the configuration logs for every affected filesystem using the --
writeconf flag to tunefs.lustre, as shown in the second step of the section.
3. If the MGS NID is also changing, communicate the new MGS location to each
server. Type:
tunefs.lustre --erase-param --mgsnode= --writeconf \
/dev/...
4.2.3.4 Aborting Recovery
When starting a target, abort the recovery process. Type:
4-14 Lustre 1.6 Operations Manual • September 2008