From: Daniel Lang <dl@leo.org> To: dxoch <dxoch@escape.gr>, freebsd-stable@FreeBSD.ORG Subject: Re: Vinum Question Message-ID: <20010105141224.E17176@atrbg11.informatik.tu-muenchen.de> In-Reply-To: <3A55B92E.A570E938@escape.gr>
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Hi Jim, [..] > Is there is any chance that vinum-related options in the loader.conf > (vinum_load ="YES") > can help me to boot from a vimum volume, or this is completely > irrelevant? I guess so. I know of 'vinum_load="YES"' only in /etc/rc.conf, not loader.conf or kernel.conf. Although I guess you could immediately load the vinum.ko, before booting the kernel (i.e. load the kernel, load the module along with other modules like splash, then boot the kernel), but this does not help you to boot from a vinum device. The problem is, that in FreeBSD, the bootstrap loaders and the kernel reside in the root-partition. The booting process is described very good in http://www.freebsd.org/handbook/boot.html You will notice that each stage just knows as much about the the disks/filesystem as it needs. So boot1 knows about the disklabel and slices to find boot2 boot2 knows about about UFS/FFS to find /boot/loader or /kernel. Themselves they reside in the MBR, or the boot-sector of the slice. Although loader is more sophisticated, it does not know about vinum, too. The first thing to know about vinum is the kernel with the vinum module loaded. In order to really boot from a vinum device, previous stages also have to know (at least something) about vinum devices. This is not the case, and I guess very difficult to implement. If you look at other OSes which allow booting from managed volumes, you may notice, that they have a special boot-filesystem (e.g. /stand, /boot), which must meet certain requirements, (like contigous block allocation, the first partition on disk/slice, etc). I guess it would be really painful to try to provide this functionality, with many drawbacks (I guess most in code-stability), huge effort required and little advantages. If you need average security agains disk-crashes, you can keep your data in vinum-volumes and back up the root-partition on a regular basis e.g. with dd. If you really need more security, go and buy a SCSI-SCSI raid-controller, which is seen as one or more single disks, independent of its real disks and configuration. You save yourself lots of trouble. Ok, this is just my opinion, based on some experience. Best regards, Daniel -- IRCnet: Mr-Spock - Burn them to ashes, then burn the ashes. - *Daniel Lang * dl@leo.org * +49 89 289 25735 * http://www.leo.org/~dl/* To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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