- <para>For best results, use RAID 5 with 5 or 9 disks or RAID 6 with 6 or 10 disks, each on a different controller. The stripe width is the optimal minimum I/O size. Ideally, the RAID configuration should allow 1 MB Lustre RPCs to fit evenly on a single RAID stripe without an expensive read-modify-write cycle. Use this formula to determine the <emphasis>
- <literal><stripe_width></literal>
- </emphasis>, where <emphasis>
- <literal><number_of_data_disks></literal>
- </emphasis> does <emphasis>not</emphasis> include the RAID parity disks (1 for RAID 5 and 2 for RAID 6):</para>
- <screen><emphasis><stripe_width_blocks></emphasis> = <emphasis><chunk_blocks></emphasis> * <emphasis><number_of_data_disks></emphasis> = 1 MB </screen>
- <para>If the RAID configuration does not allow <emphasis>
- <literal><chunk_blocks></literal>
- </emphasis> to fit evenly into 1 MB, select <emphasis>
- <literal><chunkblocks></literal>
- </emphasis><emphasis>
- <literal><stripe_width_blocks></literal>
- </emphasis>, such that is close to 1 MB, but not larger.</para>
- <para>The <emphasis>
- <literal><stripe_width_blocks></literal>
- </emphasis> value must equal <emphasis>
- <literal><chunk_blocks>*<number_of_data_disks></literal>
- </emphasis>. Specifying the <emphasis>
- <literal><stripe_width_blocks></literal>
- </emphasis> parameter is only relevant for RAID 5 or RAID 6, and is not needed for RAID 1 plus 0.</para>
+ <para>For best results, use RAID 5 with 5 or 9 disks or RAID 6 with 6 or 10 disks, each on a different controller. The stripe width is the optimal minimum I/O size. Ideally, the RAID configuration should allow 1 MB Lustre RPCs to fit evenly on a single RAID stripe without an expensive read-modify-write cycle. Use this formula to determine the
+ <literal><replaceable>stripe_width</replaceable></literal>, where
+ <literal><replaceable>number_of_data_disks</replaceable></literal>
+ does <emphasis>not</emphasis> include the RAID parity disks (1 for RAID 5 and 2 for RAID 6):</para>
+ <screen><replaceable>stripe_width_blocks = chunk_blocks * number_of_data_disks</replaceable> = 1 MB </screen>
+ <para>If the RAID configuration does not allow
+ <literal><replaceable>chunk_blocks</replaceable></literal>
+ to fit evenly into 1 MB, select
+ <literal><replaceable>stripe_width_blocks</replaceable></literal>,
+ such that is close to 1 MB, but not larger.</para>
+ <para>The
+ <literal><replaceable>stripe_width_blocks</replaceable></literal>
+ value must equal
+ <literal><replaceable>chunk_blocks</replaceable> * <replaceable>number_of_data_disks</replaceable></literal>.
+ Specifying the
+ <literal><replaceable>stripe_width_blocks</replaceable></literal>
+ parameter is only relevant for RAID 5 or RAID 6, and is not needed for RAID 1 plus 0.</para>