Markus Wernig wrote: > Hi misc > > Is anybody aware of a document that describes how to ccd all slices > (including /) after installation?
You are wanting to RETROFIT ccd mirroring on a disk that was set up without it? No. Not going to happen easily. ccd won't do root, though you could use the ALTROOT system to nightly duplicate root for you. How often do you change the data on the root partition? Hint: you don't need to mirror root. You do need to make sure your second drive has a bootable and pretty-current root, however. That's what ALTROOT does for you. You *might* be able to do a ccd setup on the second drive, copy your primary drive to it, boot off the new secondary drive, rebuild the first drive for ccd config, then duplicate. > I've installed 3.8 generic using just one of two identical disks. Now I > need to mirror that disk onto the other one. I copied the disklabel from > the active disk over. I can of course create ccd's for each slice, but > this means newfs and data loss, and won't work because I can't umount > the root. oh, you will be unmounting the entire system. > Now I assume that my approach was intrinsically bound to fail or just > dumb wrong. I'm sorry if this is covered somewhere public - I found > references to a FAQ on MARC, but was just unable to find my question > covered in the related documentation. > One thing I came up with was to boot from install media and do it from > the shell there, then newfs and reinstall on the ccd devices. But I'm > really not quite sure. you will need to /practice/ on a non-production system. I don't care what RAID solution you use. This is a must. > The goal is to bring the box back online as fast as possible after a > disk crash and replacement, and to be then able to rebuild the raidset > online (dd is fine). rebuilding with dd is done OFF LINE. You can't duplicate a live file system. You also want to make sure your ccd'd partitions are as small as you can get away with, yes, with most of your disk unused. That's to get rebuild time down as low as possible. Are you working with a system with so much dynamic data that you can't use a nightly (or weekly) dump/restore to a second drive? This can be easily done after initial install. You can't easily retrofit S/W RAID into an already configured system. Nick.
