On Tue, 14 Oct 2003, Hermann Himmelbauer wrote: > On Tuesday 14 October 2003 13:34, skopel@english.fsu.edu wrote: > > I have been following the discussion of swap on raid 1 and I just want to > > clarify something... I have my swap on /dev/md1, which is a raid1 device > > consisting of /dev/hda2 and /dev/hdc2. > > If one of the drives fails (either hda or hdc), I think the swap will be > > duplicated on the other and the box will continue merrily on, right? > > thanks > > Basically, that's what I hope. > > Anyway - what exactly happens when a PATA harddisk dies? Will this only lead > to logentries in the syslog, or will this crash the machine due to hardware > reasons? Who knows. I do know that if you plug the cable into an IDE drive the wrong way up, the processor won't start, so I guess it's possible that a failing IDE drive can take out the entire PC if you are unlucky. > Probably there would also be a difference if you would do RAID on > the same channel (e.g. hda, hdb) as a mulfunction of one device could jam the > whole IDE channel. This is generally bad. Don't do it. See archives and HowTos for more reasons not to. I've had it personally happen to me (ie. a failing drive, not part of a RAID set that time, caused the other drive on the cable to be unreachable) > The same thing can apply to SCSI, too - I once experienced this myself > when a fautly SCSI-CDROM jammed the whole SCSI-bus and crashed my > machine. > > I hope that SATA will be a lot less critical, it should support > hotplugging (at least with SATA 1.1, it's a pity that it's not supported > with 1.0 right away) and there is only one device per channel. In theory you can hot-plug (and unplug) an IDE drive, with various hardware caddys and incantations of hdparm, etc. to spin it down and remove it from the kernel, but I don't recomend it. The last time I had a real drive failure which Software RAID coped very well with, I scheduled a maintenance reboot and changed the drive then. Gordon - 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
