- <indexterm>
- <primary>Lustre</primary>
- <secondary>striping</secondary>
- </indexterm>
- <indexterm>
- <primary>striping</primary>
- <secondary>overview</secondary>
- </indexterm> Lustre File System and Striping</title>
- <para>One of the main factors leading to the high performance of Lustre file systems is the
- ability to stripe data across multiple OSTs in a round-robin fashion. Users can optionally
- configure for each file the number of stripes, stripe size, and OSTs that are used.</para>
- <para>Striping can be used to improve performance when the aggregate bandwidth to a single
- file exceeds the bandwidth of a single OST. The ability to stripe is also useful when a
- single OST does not have enough free space to hold an entire file. For more information
- about benefits and drawbacks of file striping, see <xref linkend="dbdoclet.50438209_48033"
- />.</para>
- <para>Striping allows segments or 'chunks' of data in a file to be stored on
- different OSTs, as shown in <xref linkend="understandinglustre.fig.filestripe"/>. In the
- Lustre file system, a RAID 0 pattern is used in which data is "striped" across a
- certain number of objects. The number of objects in a single file is called the
- <literal>stripe_count</literal>.</para>
- <para>Each object contains a chunk of data from the file. When the chunk of data being written
- to a particular object exceeds the <literal>stripe_size</literal>, the next chunk of data in
- the file is stored on the next object.</para>
- <para>Default values for <literal>stripe_count</literal> and <literal>stripe_size</literal>
- are set for the file system. The default value for <literal>stripe_count</literal> is 1
- stripe for file and the default value for <literal>stripe_size</literal> is 1MB. The user
- may change these values on a per directory or per file basis. For more details, see <xref
- linkend="dbdoclet.50438209_78664"/>.</para>
- <para><xref linkend="understandinglustre.fig.filestripe"/>, the <literal>stripe_size</literal>
- for File C is larger than the <literal>stripe_size</literal> for File A, allowing more data
- to be stored in a single stripe for File C. The <literal>stripe_count</literal> for File A
- is 3, resulting in data striped across three objects, while the
- <literal>stripe_count</literal> for File B and File C is 1.</para>
- <para>No space is reserved on the OST for unwritten data. File A in <xref
- linkend="understandinglustre.fig.filestripe"/>.</para>
- <figure>
- <title xml:id="understandinglustre.fig.filestripe">File striping on a Lustre* file
- system</title>
+ <indexterm>
+ <primary>Lustre</primary>
+ <secondary>striping</secondary>
+ </indexterm>
+ <indexterm>
+ <primary>striping</primary>
+ <secondary>overview</secondary>
+ </indexterm>Lustre File System and Striping</title>
+ <para>One of the main factors leading to the high performance of Lustre
+ file systems is the ability to stripe data across multiple OSTs in a
+ round-robin fashion. Users can optionally configure for each file the
+ number of stripes, stripe size, and OSTs that are used.</para>
+ <para>Striping can be used to improve performance when the aggregate
+ bandwidth to a single file exceeds the bandwidth of a single OST. The
+ ability to stripe is also useful when a single OST does not have enough
+ free space to hold an entire file. For more information about benefits
+ and drawbacks of file striping, see
+ <xref linkend="file_striping.considerations" />.</para>
+ <para>Striping allows segments or 'chunks' of data in a file to be stored
+ on different OSTs, as shown in
+ <xref linkend="understandinglustre.fig.filestripe" />. In the Lustre file
+ system, a RAID 0 pattern is used in which data is "striped" across a
+ certain number of objects. The number of objects in a single file is
+ called the
+ <literal>stripe_count</literal>.</para>
+ <para>Each object contains a chunk of data from the file. When the chunk
+ of data being written to a particular object exceeds the
+ <literal>stripe_size</literal>, the next chunk of data in the file is
+ stored on the next object.</para>
+ <para>Default values for
+ <literal>stripe_count</literal> and
+ <literal>stripe_size</literal> are set for the file system. The default
+ value for
+ <literal>stripe_count</literal> is 1 stripe for file and the default value
+ for
+ <literal>stripe_size</literal> is 1MB. The user may change these values on
+ a per directory or per file basis. For more details, see
+ <xref linkend="file_striping.lfs_setstripe" />.</para>
+ <para>
+ <xref linkend="understandinglustre.fig.filestripe" />, the
+ <literal>stripe_size</literal> for File C is larger than the
+ <literal>stripe_size</literal> for File A, allowing more data to be stored
+ in a single stripe for File C. The
+ <literal>stripe_count</literal> for File A is 3, resulting in data striped
+ across three objects, while the
+ <literal>stripe_count</literal> for File B and File C is 1.</para>
+ <para>No space is reserved on the OST for unwritten data. File A in
+ <xref linkend="understandinglustre.fig.filestripe" />.</para>
+ <figure xml:id="understandinglustre.fig.filestripe">
+ <title>File striping on a
+ Lustre file system</title>