Lustre 1.6 Operations Manual

Is it possible to change the IP address of a OST? MDS?
Change the UUID?
The IP address of any node can be changed, as long as the rest of the machines in the
cluster are updated to reflect the new location. Even if you used hostnames in the
xml config file, you need to regenerate the configuration logs on your metadata
server.
It is also possible to change the UUID, but unfortunately it is not very easy as two
binary files would need editing.
How do I set striping on a file?
To stripe a file across OSTs with stripesize of blocks per stripe, run:
lfs setstripe
This creates "new_filename" (which must not already exist).
We strongly recommend that the stripe_size value be 1MB or larger (size in bytes).
Best performance is seen with one or two stripes per file unless it is a file that has
shared IO from a large number of clients, when the maximum number of stripes is
best (pass -1 as the stripe count to get maximum striping).
The stripe_offset (OST index which holds the first stripe, subsequent stripes are
created on sequential stripes) should be "-1" which means allocate stripes in a roundrobin
manner. Abusing the stripe_offset value leads to uneven usage of the OSTs and
premature filesystem usage.
Most users want to use:
lfs setstripe 2097152 -1 N
Or use system-wide default stripe size:
lfs setstripe 0 -1 N
You may want to make a simple wrapper script that only accepts the
parameter. Usage info via "lfs help setstripe".
D-8 Lustre 1.6 Operations Manual • September 2008