Lustre 1.6 Operations Manual

Generally, a good stripe size for sequential I/O using high-speed networks is
between 1 MB and 4 MB. Stripe sizes larger than 4 MB do not parallelize as
effectively because Lustre tries to keep the amount of dirty cached data below 32 MB
per server (with the default configuration).
Writes which cross an object boundary are slightly less efficient than writes which go
entirely to one server. Depending on your application's write patterns, you can assist
it by choosing a stripe size with that in mind. If the file is written in a very consistent
and aligned way, make the stripe size a multiple of the write() size.
The choice of stripe size has no effect on a single-stripe file.
25.2 Displaying Files and Directories with lfs
getstripe
Use lfs to print the index and UUID for each OST in the filesystem, along with the
OST index and object ID for each stripe in the file. For directories, the default
settings for files created in that directory are printed.
lfs getstripe
Use lfs find to inspect an entire tree of files.
lfs find [--recursive | -r] ...
If a process creates a file, use the lfs getstripe command to determine which
OST(s) the file resides on.
Using ‘cat’ as an example, run:
$ cat > foo
In another terminal, run:
$ lfs getstripe /barn/users/jacob/tmp/foo
OBDS
25-4 Lustre 1.6 Operations Manual • September 2008