> -----Original Message----- > From: centos-bounces at centos.org > [mailto:centos-bounces at centos.org] On Behalf Of Ruslan Sivak > Sent: Friday, May 11, 2007 3:27 PM > To: CentOS mailing list > Subject: Re: [CentOS] Re: Anaconda doesn't support raid10 > > Chris Croome wrote: > > Hi > > > > On Fri 11-May-2007 at 09:38:22AM -0400, Ross S. W. Walker wrote: > > > >>> The entire use all four disks for /boot makes no sense if > two disks > >>> belonging to the same mirror for the lvm go down. Please stop this > >>> nonsense about surviving everything to no benefit. You can have > >>> three disks fail and still have a working /boot. For what? > >>> > >> I think the idea of the 4 partition raid1 was more of, > what else is he > >> going to do with the 200MB at the beginning of each disk > which he has > >> because of partition symmetry across drives? > >> > >> Makes sense to just dup the partition setup from one to > the other and > >> now with grub and a working /boot on each disk the order > of the drives > >> is no longer important, he can take all 4 out, play 4 disk > monty, slap > >> them back in and the system should come up without a problem. > >> > > > > FWIW this is what I did with the last server I built which > had 4x500gb > > drives -- a RAID 1 /boot on 4 drives. The trick for this is > to edit your > > grub.conf so that you can boot off any drive and run > grub-install on all > > 4 drives, also you have to remember to manually edit your grub.conf > > after each kernel upgrade to add the 3 extra disks: > > > > title CentOS (2.6.18-8.1.1.el5xen) Disk 0 > > root (hd0,0) > > kernel /xen.gz-2.6.18-8.1.1.el5 > > module /vmlinuz-2.6.18-8.1.1.el5xen ro > root=/dev/VolGroup00/Root > > module /initrd-2.6.18-8.1.1.el5xen.img > > title CentOS (2.6.18-8.1.1.el5xen) Disk 1 > > root (hd1,0) > > kernel /xen.gz-2.6.18-8.1.1.el5 > > module /vmlinuz-2.6.18-8.1.1.el5xen ro > root=/dev/VolGroup00/Root > > module /initrd-2.6.18-8.1.1.el5xen.img > > title CentOS (2.6.18-8.1.1.el5xen) Disk 2 > > root (hd2,0) > > kernel /xen.gz-2.6.18-8.1.1.el5 > > module /vmlinuz-2.6.18-8.1.1.el5xen ro > root=/dev/VolGroup00/Root > > module /initrd-2.6.18-8.1.1.el5xen.img > > title CentOS (2.6.18-8.1.1.el5xen) Disk 3 > > root (hd3,0) > > kernel /xen.gz-2.6.18-8.1.1.el5 > > module /vmlinuz-2.6.18-8.1.1.el5xen ro > root=/dev/VolGroup00/Root > > module /initrd-2.6.18-8.1.1.el5xen.img > > > > If I had read this thread before I set up this machine I'd have used > > RAID 6 from the rest of the space, but I used RAID 5 with a > hot spare, > > with LVM on top of that. > > > > Before the machine was moved to the colo I tried pulling > disks out while > > it was running and this worked without a problem, which was nice :-) > > > > Chris > > > > > > > Chris, > > I didn't have to install grub on any of the other volumes, and the > server seemed to do well after drive failure (I pulled out > drives 1 and > 3). > In my opinion, neither raid5 or raid6 makes sense with 4 > drives, as you > will get the same amount of space with raid10, but much better > performance and availability (although raid6 is supposed to > withstand 2 > drive failures, in my tests it has not done well, and neither has > raid5). As you might've read from the thread, if you want to > put the / > volume on the raid10, it will not be possible during the install, but > you can set up 2 raid1 volumes, and do an LVM stripe across > them which > should yield comparable performance. I think if you setup the 4 disk raid1 at boot grub gets installed on each as part of the install process. You'd only need to do it yourself if you put a new disk to replace a failed one, then just run grub-install on it. -Ross ______________________________________________________________________ This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, please immediately notify the sender and permanently delete the original and any copy or printout thereof.