On 04/13/13 21:01, Stuart Henderson wrote: > On 2013/04/14 01:27, Stuart Henderson wrote: >> On 2013/04/13 16:50, Raymond Lillard wrote: ... >> > First problem is: >> > When I boot in step 3, all four disks appear in the roll call as expected >> > in dmesg, but when I try the command "disklabel sd3", rsd3 is not found. >> > >> > Why ??? This seems like a bug to me. > > The device nodes are normally created in the installer when needed, > I think this is to save inodes on the ramdisk.
yep. Curiously, the one time I really ran into a problem here was on a sparc64 system. Had a lot of SCA disks to clear...and an idle E450. For those who haven't seen an E450, they look like a Star Trek Borg Cube, and hold a snootload of disks (iirc, in this case, "1 snootload" = 20 disks, across a bunch of SCSI channels, iirc, four disks per channel). Perfect for zeroing disks. 'cept, it turns out, at least at that time, there wasn't sufficient inodes for that many sd(4) devices on the bsd.rd kernel. That's ok, turned out my E450 didn't have enough SCSI controllers in it to do all 20 disks at once anyway. [another message] >>>> >>> 1: I zero the first 10MB of all four disks with dd >>>> >>> 2: I power cycle the box and boot form a cdrom snapshot from April 10 >>>> >>> 3: I use disklabel check that all disks have only C partitions >> > >> > I'm not sure offhand where softraid metadata are stored to suggest >> > how much needs blanking, but obviously this must be further into the >> > disk than the partition table, you probably just need to go a bit >> > further with blanking. When I'm doing this I normally don't specify >> > a count and just hit ^C after a few seconds...not exactly scientific >> > but works for me. > > Man page softraid(4) gives an example that indicates zero'ing the > first megabyte is sufficient. first megabyte of what? The man page is having you clear the first 1MB of the assembled disk, not the raw disks. If your softraid partition is not starting in the first 1MB of RAID partition, zeroing the disk itself does nothing, as it misses the softraid metadata. I disagree with the man page, which has you clearing 1MB of the /assembled pseudo-disk/, I've had much better luck clearing 1MB (though I usually use Stuart's "wait a moment and hit CTRL-C" process) of each /RAID partition/ *before* assembling the disk. There may be some logic to clearing the first bit of the disk AFTER creation, too, in that's where a lot of important tidbits are stored, might be nice to have RAID consistent data there. Nick.
