I agree the patch isn't a complete solution to all that potentially ails raidtools. All the patch does is address one specific case -- the case where /sbin/raidstart gives up when it can't get a superblock from the first entry in raidtab, even though it could have read the superblock from one of the other entries and started the RAID. If you couldn't have started the RAID even if the initial superblock read succeeded, the patch won't do any good -- except that you'll fail trying to start the RAID instead of trying to read the superblock, which is more correct, IMO. In the specific example you listed, if the drives were listed at dev/sdb, dev/sdc, and dev/sdd but are really at /dev/sda, /dev/sdb, and /dev/sdc, the patch doesn't even come into play. Assuming /dev/sdb is listed first in the raidtab, the superblock read from /dev/sdb WILL succeed, since the former /dev/sdc has a superblock too. The only way my patch would affect the problem is if /dev/hdd happened to be listed first. I look forward to trying your complete solution. Thanks for all your work. Dale Stephenson [EMAIL PROTECTED] -----Original Message----- From: Neil Brown To: Dale Stephenson Cc: Scott Smyth; '[EMAIL PROTECTED]' Sent: 6/11/01 5:47 PM Subject: RE: failure of raid 5 when first disk is unavailable On Friday June 8, [EMAIL PROTECTED] wrote: > Here's a patch that will cause raidstart to work when it can't get the > superblock from the first drive mentioned in the raidtab. > I've also included it as an attachment in case Outlook does its evil magic > to the text. > > Basically, I changed raidlib to try starting the raid with each of the > devices in it until it either succeeds or runs out of devices. This is probably an improvement, but it is a long way from a real solution. It requires all the working devices to have device numbers that were thought to be in the array. Suppose that you have as JBOD* at /dev/sda, and a RAID at /dev/sdb /dev/sdc /dev/sdd Then you take the JBOD out, the RAID disks will appear at /dev/sda /dev/sdb /dev/sdc, and with or without your patch, you will not be able to start the array properly - it will never find /dev/sda. NeilBrown * JBOD = Just a Boring Old Disc. - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED]
