Ruslan Sivak wrote: > Toby Bluhm wrote: >> Ruslan Sivak wrote: >>> Toby Bluhm wrote: >>>> Ruslan Sivak wrote: >>>>> Feizhou wrote: >>>>>> Ruslan Sivak wrote: >>>>>>> Feizhou wrote: >>>>>>>> >>>>>>>>> I do have a SIL3114 chipset, and I think it's supposed to be >>>>>>>>> supported by device mapper. When I go to rescue mode, I see >>>>>>>>> it loading the driver for SIL3112, but nothing appears under >>>>>>>>> /dev/mapper except control. Are there instructions somewhere >>>>>>>>> on getting it to use my controller's raid? >>>>>>>> >>>>>>>> Your controller only has a bios chip. It has no raid processing >>>>>>>> capability at all. >>>>>>>> >>>>>>>> You need to use mdadm. anaconda should be able to let you >>>>>>>> create to mirrors and then create a third array that stripes >>>>>>>> those md devices, >>>>>>>> _______________________________________________ >>>>>>> Anaconda doesn't let me create a stripe raid set on top of a >>>>>>> mirror set. And it doesn't detect it when I do it manually. >>>>>>> Also the bios chip presents additional issues. I believe when I >>>>>>> don't have a raid array set up, it won't boot at all. When I >>>>>>> have it on raid10, I had trouble booting, and when I have it on >>>>>>> concatenation, everything works fine, until a drive is >>>>>>> replaced. At that point, i have to recreate the array, as >>>>>>> concatenation is not a fault tolerant set, and at this point I >>>>>>> seem to lose all my data. >>>>>> >>>>>> It won't boot at all without a raid array setup? That sounds >>>>>> really funny. >>>>>> >>>>> Actually I'm not 100% sure on this, but I think this is the case. >>>>> I believe the first time I set it up as a raid10, assuming that >>>>> linux will just ignore it. I installed centos by putting boot on >>>>> a raid1, and root on LVM over 2 raid1 sets. I had trouble getting >>>>> it to boot. >>>>>>> Is there a way to get it to use the raid that's part of the bios >>>>>>> chip? >>>>>> >>>>>> Repeat after me. There is no raid that is part of the bios chip. >>>>>> It is just a simple table. >>>>> Yes, I know this is fakeraid, aka softraid, but I was hoping that >>>>> using the drivers would make it easier to support raid 10 then >>>>> with mdadm, which seems to be impossible to get to work with the >>>>> installer. I'm not even sure why the raid10 personality is not >>>>> loaded, as it seems to have been part of the mdadm since version 1.7. >>>>>>> Something about device mapper? >>>>>> >>>>>> >>>>>> You need the fake raid driver dmraid if you are going to set up >>>>>> stuff in the bios. What version of centos are you trying to >>>>>> install? libata in Centos 5 should support this without having to >>>>>> resort to the ide drivers. >>>>>> _________________________________ >>>>> I'm trying to install centos 5 - the latest. How would I go about >>>>> using dmraid and/or libata? The installer picks up the drives as >>>>> individual drives. There is a drive on the silicon image website, >>>>> but it's for RHEL4, and I couldn't get it to work. I'm open to >>>>> using md for raid, or even LVM, if it supports it. I just want to >>>>> be able to use raid10, as I can't trust raid5 anymore. >>>>> >>>> >>>> IIRC you had two out of four new disks die? So maybe it would be >>>> more accurate to say it's your hardware you don't trust. Raid5 is >>>> used without problems by ( I assume ) many, many people, myself >>>> included. You could have a raid10 and still lose the whole array if >>>> two disks that in the same mirror die at once. I guess no software >>>> in the world can really overcome bad hardware. That's why we do >>>> backups :) >>>> >>>> Anyway, perhaps excersizing /stressing the disks for a few days >>>> without error would make you feel more confident about the HDs. >>>> >>> >>> Actually, 2 disks did not die. Due to the fact that it was a new >>> raid 5 array (or for whatever reason), it was rebuilding the array. >>> One of the drives had a media error, and this caused the whole array >>> to be lost. >>> This is exactly what this article warns about: >>> >>> http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt >> >> >> The article doesn't seem to mention the fact that if a disk in a >> mirror set dies and the remaining disk within the set starts to have >> data corruption problems, the mirror will be rebuilt from corrupted >> data. > While this is true, it's far more likely that there will be a media > error (i.e. bad sector), and that the system will notice it. With > raid 5, it will just kick out the drive, and you can say bye bye to > your data. Perhaps not totally lost, but not fun either. Force mdadm to run ; try to fix/relocate bad sector & force mdadm to run ; dd to identical disk & force mdadm to run. > With raid 10, if it happens on one of the disks in the other set, you > don't have a problem, and if it happens to the disk in the same set > (not very likely), A 1 in 3 chance of putting the two worst disks together when using 4 disk raid10. > I'm not sure what the outcome will be, but hopefully it can recover? > I have just had a windows drive have a whole bunch of bad sectors and > I was still able to boot to windows, and copy most of the data off. I > can't imagine Linux being any worse. >> I don't know what you can do at this point, though. Perhaps make 2 >> separate mirrors and rsync them? You could keep copies of changes >> that way. >> > I know there is a raid10 personality for md. I saw it in the source > code. I see people's boot logs all over the web that say this: > > md: linear personality registered as nr 1 > md: raid0 personality registered as nr 2 > md: raid1 personality registered as nr 3 > md: raid10 personality registered as nr 9 > md: raid5 personality registered as nr 4 > > Why does CentOS5 not support the raid10 personality? Do i need to > custom compile md? Do I need to custom compile the kernel? > Russ > > You have enlightened me to the raid10 module: [root at tikal ~]# locate raid10 /usr/src/kernels/2.6.9-42.0.3.EL-smp-i686/include/config/md/raid10 /usr/src/kernels/2.6.9-42.0.3.EL-smp-i686/include/config/md/raid10/module.h /usr/src/kernels/2.6.9-42.0.3.EL-smp-i686/include/linux/raid/raid10.h /usr/src/kernels/2.6.9-42.0.10.EL-i686/include/config/md/raid10 /usr/src/kernels/2.6.9-42.0.10.EL-i686/include/config/md/raid10/module.h /usr/src/kernels/2.6.9-42.0.10.EL-i686/include/linux/raid/raid10.h /usr/src/kernels/2.6.9-42.0.3.EL-i686/include/config/md/raid10 /usr/src/kernels/2.6.9-42.0.3.EL-i686/include/config/md/raid10/module.h /usr/src/kernels/2.6.9-42.0.3.EL-i686/include/linux/raid/raid10.h /lib/modules/2.6.9-42.0.3.EL/kernel/drivers/md/raid10.ko /lib/modules/2.6.9-42.0.10.EL/kernel/drivers/md/raid10.ko /lib/modules/2.6.9-42.0.3.ELsmp/kernel/drivers/md/raid10.ko [root at tikal ~]# modprobe raid10 [root at tikal ~]# lsmod | grep raid raid10 23233 0 raid1 20033 1 This is not a Centos 5 machine though, it's SL4.4. -- Toby Bluhm Midwest Instruments Inc. 30825 Aurora Road Suite 100 Solon Ohio 44139 440-424-2250