Hi Gandalf, On Wed, Jun 28, 2017 at 12:25:55PM +0200, Gandalf Corvotempesta wrote: > Hi to all > I always used hardwre raid but with my next server I would like to use mdadm. > > Some questions: > > 1) all raid controllers have proactive monitoring features, like > patrol read, consistency check and (more or less) some SMART > integration. > Any counterpart in mdadm? mdmon(8) is what you seek. Also, monitoring the kernel debug ringbuffer I can highly recommend. > 2) thanks to this features, raid controller are usually able to detect > disk issues before they cause data-loss. what about mdadm ? > > How and when do you replace disks ? Based on which params? Do you > always wait for a total failure before replacing the disk? > > Is mdadm able to notify some possible bad-things before they happens ? md doesn't do low-level management of block devices/disks; that's the job of other parts of the kernel. The block layer will report errors that you may want to act upon before md itself complains and/or the disk gets kicked from its array (which renders your array degraded, but otherwise operational), but that's usually not necessary. There's generally no need to replace a disk without any indication of serious problems (like it getting booted from the array due to I/O timeouts, for instance). > Many times in the past our raid controllers forced a bad sector > reallocation during proactive tasks like patrol read. This saved me > many times before. I've tried to not replace a disks when this > reallocation was made (it was a test server) and after some weeks the > disk failed totally. You can initiate the resilvering of array data via sysfs; check md(4) for details. -- with best regards: - Johannes Truschnigg ( johannes@xxxxxxxxxxxxxxx ) www: https://johannes.truschnigg.info/ phone: +43 650 2 133337 xmpp: johannes@xxxxxxxxxxxxxxx Please do not bother me with HTML-email or attachments. Thank you.
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