Hi Heinz, I found a definition of nested raid levels on wikipedia here http://en.wikipedia.org/wiki/Nested_RAID_levels that seems to agree with what Jason is saying. Raid10 is defined as a stripe of mirrors. -James <blockquote style='border-top: 1px solid rgb(204, 204, 204); margin: 0.8ex 0pt 0pt 0pt; padding-bottom: 1ex;'> ---------[ Received Mail Content ]---------- Subject : RE: raid10 vs raid01 type in dmraid Date : Thu, 21 Jun 2007 09:23:32 -0700 From : "Gaston, Jason D" <jason.d.gaston@intel.com> To : <mauelshagen@redhat.com> Cc : "ATARAID (eg, Promise Fasttrak, Highpoint 370) related discussions" <ataraid-list@redhat.com> >-----Original Message----- >From: Heinz Mauelshagen [mailto:mauelshagen@redhat.com] >Sent: Thursday, June 21, 2007 3:38 AM >To: Gaston, Jason D >Cc: mauelshagen@redhat.com; ATARAID (eg, Promise Fasttrak, >Highpoint 370) related discussions >Subject: Re: raid10 vs raid01 type in dmraid > >On Tue, Jun 19, 2007 at 03:52:14PM -0700, Gaston, Jason D wrote: >> I think that the array for nested raid levels, in metadata.c, may be >> upside down. When I build a raid0+1 with Intel or Nvidia (one mirror >> array of two stripe arrays), it is reported as a "raid10" >with [dmraid >> -s], this should be "raid01". If I reverse the nesting to raid10, in >> Intel (one stripe array of two mirror arrays), it is reported as a >> "raid01" with [dmraid -s], this should be "raid10". >> >> Can we just reverse the array in metadata.c? > >Nope, this is a question of the definition of RAID10 and >RAID01 (or RAID0+1). > >I use RAID10 for a mirror on top of 2 (or more) striped sets vs. >RAID01 for a stripe on top of 2 (or more) mirror sets in dmraid. > >Ie. looking at the device stack from the top to the bottom. > >So the example you made above (Intel or NVidia) with one mirror of >2 striped arrays is a RAID10 by that definition. > >Heinz > >> >> From: >> static const char *stacked_ascii_type[][5] = { >> { "raid10", "raid30", "raid40", "raid50", "raid60" }, >> { "raid01", "raid03", "raid04", "raid05", "raid06" }, >> }; >> >> To: >> static const char *stacked_ascii_type[][5] = { >> { "raid01", "raid03", "raid04", "raid05", "raid06" }, >> { "raid10", "raid30", "raid40", "raid50", "raid60" }, >> >> }; >> >> Thanks, >> >> Jason > Where did we get that definition for RAID10 from? Everywhere that I look I see the reverse definition for RAID10 vs RAID 0+1. Nvidia even defines their RAID as 0+1 in their OROM and MediaShield documentation. Thanks, Jason _______________________________________________ Ataraid-list mailing list Ataraid-list@redhat.com https://www.redhat.com/mailman/listinfo/ataraid-list </BLOCKQUOTE> <div> <hr style="width:85%;margin-left:0px;text-align:left"/> Want to change your life? Find the perfect job with Lycos Jobs. Career Advice. Job Resources & Recommendations. <a href="http://www.careerbuilder.com/?lr=cblycos&siteid=lycoshp7" target="_blank">Post your resume & find a job match!</a> </div>