Messages in this thread | | | Date | Fri, 17 May 2002 11:29:42 -0700 | From | Mike Fedyk <> | Subject | Re: Thoughts on using fs/jbd from drivers/md |
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On Thu, May 16, 2002 at 04:17:49PM +0100, Stephen C. Tweedie wrote: > Hi, > > On Thu, May 16, 2002 at 03:54:20PM +1000, Neil Brown wrote: > > The basic idea is to provide journaling for md/RAID arrays. There > > are two reasons that one might want to do this: > > 1/ crash recovery. Both raid1 and raid5 need to reconstruct the > > redundancy after a crash. For a degraded raid5 array, this is not > > possible and you can suffer undetected data corruption. > > If we have a journal of recent changes we can avoid the > > reconstruction and the risk of corruption. > > Right. The ability of soft raid5 to lose data in degraded mode over a > reboot (including data that was not being modified at the time of the > crash) is something that is not nearly as widely understood as it > should be, and I'd love for us to do something about it.
Are there workarounds to avoid this problem?
What does it take to trigger the corruption?
I ask this because I have used a degraded raid5 because the source drive would become a member, but I needed to copy the data first. While doing so, I had to reboot a couple times to reconfigure the boot loader. All seems to be working fine on the system today though.
Thanks,
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