By Gunter Roeth on Mar 03, 2009
As already said, Lustre stores files, or blocks of files, that are
considered as objects, of one or more OSTs. This is called striping in
the Lustre terminology. You will need striping :
- if your file is too large to be stored on a single OST.
- if the required aggregate bandwidth for a single file cannot be offered by a single OST.
- if a client, i.e., your program running on the cluster, needs more bandwidth than a single OSS can offer.
Lustre allows you to configure the number of stripes, the stripesize and the servers (OSS) to use, for every file, directory or directory-tree.Practically, the smallest recommended stripe size is 512 KB because Lustre tries to batch I/O into 512 KB chunks over the network. This is a good amount of data to transfer at one time.
Perhaps you will see a problem, that the file that you are using is considered as a single object. In this case, the file (or object) is stored on a single OST, i.e., a single disk, and you do not see any performance improvement.[Read More]