Heinz.Mauelshagen@xxxxxxxxxxxxx Fri, Mar 25, 2005 at 02:12:33AM -0800, Molle Bestefich wrote: > Roland wrote: > > What happend if for example 1 disk of a mirror raid gets broken, has bad sectors? > > Will there be an appropriate error message > > Probably up to the device mapper mirror target (dm-mirror.(k)o), not > dmraid. Hopefully you will get an error message in the syslog, which > you can use your favorite syslog daemon to direct to somewhere useful. > Not sure what HighPoint's proprietary driver does. I think it tries > to write the faulted sector back from the working drive immediately, > thus freezing the operating system meanwhile. All personal guesswork, > though. If you can't get an answer here, you could try the > device-mapper mailing list. That's basically right. The mirror target in device-mapper needs some enhancements still (ie, status reports on io failure, read balancing) and dmraid needs a daemon, which monitors device failures at the device-mapper status interface and handles those (eg, fire up a spare drive and rebuild the set; try to store status information about the failure in the vendor specific metadata). > > > and will the metadata be changed? Not yet. dmraid daemon I'm working on will do. > Probably ought to be, but I think it won't. > AFAICT, dmraid currently only tells the device-mapper how to assemble > RAID arrays, it doesn't stay alive in any way in order to reflect > drive status to array metadata or such. Correct for now. I wanted to give users access to their data in the first development step and add monitoring in a sencond one, which I'm working on now. > And I'm pretty sure that > dm-mirror doesn't do it. As I remember it, dmraid comes with good > concise documentation, should be mentioned there. > > > I am running dmraid with a hpt37x mirror (raid 1) on 2.6.10 debian amd64. > > > When I copy some large files onto the raid, my computer "freezes" and I dont > > get any message in syslog or dmesg. I load dmraid in verbose mode and also > > have enabled debug symbols but dont see any > > error message. > > > Whats wrong? > Not sure. I've seen the exact same thing happen with HPT37x's with > proprietary drivers, so perhaps it's a hardware kink that occurs under > specific circumstances. Then again, maybe it's not, I've also seen > numerous bugs in the Linux IDE layer. And there's recent bug fixes to device-mapper as well. > > > Is this a problem of the device mapper? > Could be. That or the HighPoint driver. How reproducible is the > problem? If you have a backup or your data is expendable, your could > try running parallel dd's to write out a large amount of data to each > drive in parallel. If it still freezes, it's not the device-mapper > ;-). Yes, move layers out of the test configuration and nail the drives, interfaces, cables, ... > > > Any Idea? > Try upgrading to kernel 2.6.11, and upgrade the device-mapper too.. > I think the next step then is probably to enable SysRq support in > your kernel, read a kernel debugging tutorial and see if you can find > out where it's frozen / deadlocked / infinte-loop'ed / what not. Definitely needed to make this transparent. Hammering as close to the HW as possible is a good point to start with. > If you really want to know what's happened, in order to make 100% > sure that it doesn't occur again, you should of course debug against > your current kernel version. Find the bug, and check for it's > existance in newer versions of kernel / whatever. But if you go this > path, you probably can't expect any help whatsoever from the kernel > hackers or any such. > > HTH... > > _______________________________________________ > > Ataraid-list@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/ataraid-list Regards, Heinz -- The LVM Guy -- *** Software bugs are stupid. Nevertheless it needs not so stupid people to solve them *** =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Heinz Mauelshagen Red Hat GmbH Consulting Development Engineer Am Sonnenhang 11 56242 Marienrachdorf Germany Mauelshagen@xxxxxxxxxx +49 2626 141200 FAX 924446 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
