} -----Original Message----- } From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid- } owner@xxxxxxxxxxxxxxx] On Behalf Of Bill Davidsen } Sent: Saturday, September 16, 2006 10:29 AM } To: Tuomas Leikola } Cc: Bodo Thiesen; Linux RAID } Subject: Re: proactive-raid-disk-replacement } } Tuomas Leikola wrote: } } > On 9/10/06, Bodo Thiesen <bothie@xxxxxx> wrote: } > } >> So, we need a way, to feedback the redundancy from the raid5 to the } >> raid1. } > } > <snip long explanation> } > } > Sounds awfully complicated to me. Perhaps this is how it internally } > works, but my 2 cents go to the option to gracefully remove a device } > (migrating to a spare without losing redundancy) in the kernel (or } > mdadm). } > } > I'm thinking } > } > mdadm /dev/raid-device -a /dev/new-disk } > mdadm /dev/raid-device --graceful-remove /dev/failing-disk } > } > also hopefully a path to do this instead of kicking (multiple) disks } > when bad blocks occur. } } } Actually, an internal implementation is really needed if this is to be } generally useful to a non-guru. And it has other possible uses, as well. } if there were just a --migrate command: } mdadm --migrate /dev/md0 /dev/sda /dev/sdf } as an example for discussion, the whole process of not only moving the } data, but getting recovered information from the RAID array could be } done by software which does the right thing, creating superblocks, copy } UUID, etc. And as a last step it could invalidate the superblock on the } failing drive (so reboots would work right) and leave the array running } on the new drive. } } But wait, there's more! Assume that I want to upgrade from a set of } 250GB drives to 400GB drives. Using this feature I could replace a drive } at a time, then --grow the array. The process for doing that is complex } currently, and many manual steps invite errors. I like the migrate option or whatever you want to call it. However, if the disk is failing I would want to avoid reading from the failing disk and reconstruct the data from the other disks. Only reading from the failing disk if you find a bad block on another disk. This would put less strain on the failing disk possibly allowing it to last long enough to finish the migrate. Your data would remain redundant throughout the process. However if I am upgrading to larger disks it would be best to read from the disk being replaced. You could even migrate many disks at the same time. Your data would remain redundant throughout the process. Guy } } -- } bill davidsen <davidsen@xxxxxxx> } CTO TMR Associates, Inc } Doing interesting things with small computers since 1979 } } - } To unsubscribe from this list: send the line "unsubscribe linux-raid" in } the body of a message to majordomo@xxxxxxxxxxxxxxx } More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
