>-----Original Message----- >From: Heinz Mauelshagen [mailto:mauelshagen@xxxxxxxxxx] >Sent: Tuesday, June 26, 2007 12:58 AM >To: Gaston, Jason D >Cc: mauelshagen@xxxxxxxxxx; ATARAID (eg, Promise Fasttrak, >Highpoint 370) related discussions >Subject: Re: raid10 vs raid01 type in dmraid > >On Mon, Jun 25, 2007 at 10:18:14AM -0700, Gaston, Jason D wrote: >> > >> >Eg, PC Magazine: >> >"RAID 10, RAID 100 - Speed and Fault Tolerance >> >RAID 10 is RAID 1 + 0. The drives are striped for performance >> >(RAID 0), and all striped drives are duplicated (RAID 1) for >> >fault tolerance." >> > >> >Yes, I konw, there's different (aargh!) definitions out there. >> > >> >Like I said: the top -> bottom of the stack definition is preferable >> >to me (you reach the mirror first and the stripe second >while walking >> >the stack from the top to the bottom). >> > >> >We just got to hold on to one definition in dmraid, >> > >> >Heinz >> > >> >> Ok, so the dmraid definition is not going to change. > >I'ld much rather avoid it :-) > >> >> Do you see an advantage in putting the RAID1 vs. RAID0 on >the bottom for >> being able to perform rebuilds easier? I need to decide >which way to do >> with isw. > >Talking about either a mirror on top of stripes or a stripe on >top of mirrors, >it is merely a question of IO minimization on rebuilds. > >Ie. when a stripe below a mirror breaks, you've got to >resilver the whole >stripe set, hence writing 2 or more drives rather than just one disk in >a mirror set beneath a stripe. > > >With respect to ease of rebuilds at the programming level, there's no >difference in changing the mapping of a top level mirror to do a full >resync vs. a bottom level mirror. > > >Getting back to your decision: you could support both ;-) > >Cheers, >Heinz > >> >> Thanks, >> >> Jason > After adding support for RAID10 to isw.c, what will we need to do in order for this to be supported in anaconda, so that we can install to a RAID10 nested volume? I don't see support for nested RAID levels in dmraid.py. Thanks, Jason _______________________________________________ Ataraid-list mailing list Ataraid-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/ataraid-list
