Override File System Striping Defaults

Purpose of and options for over-riding file systems striping defaults.

Each Lustre file system is built with a default stripe pattern that is specified in fs_name.fs_defs. However, users may select alternative stripe patterns for specific files or directories with the lfs setstripe command. For more information, see the lfs(1) man page.

File Striping

The lfs setstripe command has the following syntax, lfs setstripe -s stripe_size -c stripe_count -i stripe_start filename.

This example creates the file, npf, with a 2MB (2097152 bytes) stripe that starts on OST0 (0) and stripes over two object storage targets (OSTs) (2).

$ lfs setstripe -s 2097152 -c 2 -i 0 npf

Here the -s specifies the stripe size, the -c specifies the stripe count, and the -i specifies the index of the starting OST.

The first two megabytes, bytes 0 through 2097151, of npf are placed on OST0, and then the third and fourth megabytes, 2097152-4194303, are placed on OST1. The fifth and sixth megabytes are again placed on OST0 and so on.

The following special values are defined for the lfs setstripe options.

stripe_size=0: Uses the file system default for stripe size.
stripe_start=-1: Uses the default behavior for setting OST values.
stripe_count=0: Uses the file system default for stripe count.
stripe_count=-1: Uses all OSTs.