On Tue, Feb 05, 2002 at 06:51:46PM +0200, Cajoline wrote: > Hi. ... > As for relocating the drives, someone told me that just moving them > along the new ide slots so the initial device sequence (that I used in > the raidtab when I mkraid'ed) is preserved would be enough for that > matter. However, I'm afraid that's not right. This is the first > question. If you use persistent superblocks, the RAID layer will figure out by itself when you move the disks. The superblock will contain the data telling "this partition is number X in the array". So you should be safe there. > > After looking around, I came across the raidreconf utility at > http://unthought.net/raidreconf/index.shtml The utility is meant for re-configuring arrays, meaning, *) conversion of chunk sizes (eg. 32 to 64k chunks) *) conversion of raid levels (eg. RAID-0 to RAID-5) *) conversion of raid layouts (eg. adding more disks to existing arrays) It is not needed for moving a disk from one channel to another. > First of all, that page as well as the HOWTO included in the package > available there mentions that this tool was written by Jakob Østergaard > but it is currently maintained by Danny Cox. The HOWTO also mentions > that raidreconf can be obtained from http://oss.connex.com. However, > that host seems to be down in the last few days. The version of > raidreconf-latest.tgz available on the page above is dated November 1, > 2001 (120092 bytes). Does anyone know if there is any more recent > version, where it can be found and who is the current maintainer? I suppose that I am the maintainer. Danny "almost-officially" took over the maintainership, but it's been a very long time since I've heard from him. However, very little maintenance has been going on. I have used the tool every now and then, with good success - but I do not use it on a daily base (far from it!), so there is not big development happening right now. Also, every now and then someone says they will try it out, but I have yet to get a failure report (and I kind of miss success reports as well - hint ! ;) The version on my web page is the most recent, unless Quantum has been working on this tool behind closed doors, which I have no reason to believe they would (they willingly gave me back the code with their bug-fixes after a period where I was too busy to fix the last bugs, and where they were interested in the tool - Kudos to them, and Danny and the other great people there !). > So the last question is this. I know I do have to use raidreconf for > adding a new disk to the array, but do I also have to use it if I just > relocate the drives to different IDE slots? Does it make any difference > if I maintain the initial sequence of the devices, as it was in raidtab > at the time of mkraid'ing? Or is there any other similar trick one can > do to do the relocation, avoiding the use of raidreconf? You don't need raidreconf for relocating disks. > Apart from the possible problems one may come across with raidreconf, as > warned by the authors, I also read that raidreconf will take a > considerable amount of time to complete the conversion, so if there is a > way to do the relocation without using raidreconf, I would prefer it, to > stay on the safe side. Yes, raidreconf runs can be fairly time consuming. A chunk-size conversion on a 40-60 GB RAID-0 can take several hours. It all depends very much on the amount of memory in the machine - raidreconf will make generous use of whatever RAM you have in the machine, but converting 100's of GB arrays on a 32 MB box is going to be very time consuming (I did the 40 GB 32->64K chunk-size (RAID-0) conversion on a 48 MB box, and I think it took around 4 or 6 hours - but that was a silly experiment really). On RAID-0, I don't know of any other way than using raidreconf for adding disks. You could, however, create a new linear array over your existing array and the new disk. With a little care, some -f options for mkraid, and a following ext2resize, it should be quite possible (and safe if you do not make mistakes and do not have a power outage... ;) (On a related note: raidreconf is rather sensitive to power outages - it does not currently keep a journal or log over moved blocks, so there is currently no way to recover data if the reconfiguration is halted) -- ................................................................ : jakob@unthought.net : And I see the elder races, : :.........................: putrid forms of man : : Jakob Østergaard : See him rise and claim the earth, : : OZ9ABN : his downfall is at hand. : :.........................:............{Konkhra}...............: - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
