Lustre 1.6 Operations Manual

Can I change the striping of a file or directory after it is created?
You cannot change the striping of a file after it is created. If this is important (e.g.,
performance of reads on some widely-shared large input file) you need to create a
new file with the desired striping and copy the data into the old file. It is possible to
change the default striping on a directory at any time, although you must have write
permission on this directory to change the striping parameters.
How do I replace an OST or MDS?
The OST filesystem is simply a normal ext3 filesystem, so you can use any number
of methods to copy the contents to the new OST.
If possible, connect both the old OST disk and new OST disk to a single machine,
mount them, and then use rsync to copy all of the data between the OST filesystems.
For example:
mount -t ext3 /dev/old /mnt/ost_old
mount -t ext3 /dev/new /mnt/ost_new
rsync -aSv /mnt/ost_old/ /mnt/ost_new
ost_old/
# note trailing slash on
If you are unable to connect both sets of disk to the same computer, use:
rsync to copy over the network using rsh (or ssh with "-e ssh"):
rsync -aSvz /mnt/ost_old/ new_ost_node:/mnt/ost_new
The same can be done for the MDS, but it needs an additional step:
cd /mnt/mds_old; getfattr -R -e base64 -d . > /tmp/mdsea;
; cd /mnt/mds_new; setfattr \
--restore=/tmp/mdsea
D-10 Lustre 1.6 Operations Manual • September 2008