} -----Original Message----- } From: Ruslan Sivak [mailto:rsivak@xxxxxxxxxxxxx] } Sent: Friday, May 04, 2007 7:22 PM } To: Guy Watkins } Cc: linux-raid@xxxxxxxxxxxxxxx } Subject: Re: raid10 on centos 5 } } Guy Watkins wrote: } > } -----Original Message----- } > } From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid- } > } owner@xxxxxxxxxxxxxxx] On Behalf Of Ruslan Sivak } > } Sent: Friday, May 04, 2007 12:22 PM } > } To: linux-raid@xxxxxxxxxxxxxxx } > } Subject: raid10 on centos 5 } > } } > } I am trying to set up raid 10 and so far with no luck. I have 4 } drives, } > } and Anaconda will not let me do raid 10. mdadm doesn't have the raid } 10 } > } personality loaded. When I create the array manually like so: } > } } > } 2 drives in /dev/md11 as raid1 } > } 2 drives in /dev/md12 as raid1 } > } md11 and md12 in /dev/md10 as raid0 } > } } > } Everything looks fine from the shell, but anaconda only sees md11 and } > } md12. } > } } > } The only choice I see is to set up LVM over md11 and md12. Is this } > } really raid10? } > } } > } Russ } > } > You are making a RAID1+RAID0 array. } > Try making a real RAID10 array with 4 drives. This way you would only } have } > 1 array with 4 drives. } > } > >From the mdadm man page: } > Currently, Linux supports LINEAR md devices, RAID0 (striping), RAID1 } > (mirroring), RAID4, RAID5, RAID6, RAID10, MULTIPATH, and FAULTY. } > } > Notice RAID10 is listed, use that. Man mdadm for more info. } > } > However, I would (and do) use RAID6. With RAID6 any 2 disks can fail } > without data loss. With RAID1+RAID0, any one disk can fail, a second } > failure has a 1 in 3 chance of vast data loss. } > } > I hope this helps, } > Guy } > } > - } > } } } Guy, } } That's what I've been trying to do. Unfortunatelly, my distro, CentOS 5 } (based on RHEL 5, I believe), does not have the RAID10 personality in } the kernel. I guess I would have to compile my own kernel and load the } module through a driver disk. Would that work? Are there some } instructions somewhere I can follow? } } Russ I don't know how to make a driver disk. Also not much on making modules. >From what I know, linux only loads the RAID modules it needs. My system does not have raid0 or raid10 loaded. But both loaded when I used modprobe. I have FC6, upgraded from FC5 using yum, so maybe not 100% FC6. Anyway, you were not making a RAID10 array. You were making 2 RAID1 arrays and then 1 RAID0 array. That does not need the RAID10 module (AFAIK). If I recall, there is an issue of nesting arrays like you were doing. The problem was related to auto starting them. But I don't recall any details, and maybe it has been corrected. Guy - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
