On 11/4/19 7:21 pm, Andreas Klauer wrote:
On Wed, Apr 10, 2019 at 03:35:46PM +1000, Eyal Lebedinsky wrote:
I have a raid6 with 7 devices which is larger than needed now.
Download more things until it's just right. ;-)
One disk needs replacement
So replace it before doing anything else.
Already being done.
I will first resize (shrink) the fs, then reduce the array size (--array-size=).
mdadm --grow --raid-devices=6 should tell you the correct value for --array-size.
Then you know what exactly to shrink the filesystem to, so it's neither too large
nor too small.
but I do not know how to nominate which of the 7 devices to remove.
Not really possible.
This would be, I think, a useful feature to have.
Shrinking a RAID6 with a drive missing still has a missing drive.
Of course, you can re-sync the leftover drive afterwards.
However since you'll be getting a replacement drive anyways,
just replace the drive first. Then ... consider not shrinking it at all.
Esp. if you have plans to re-grow it later, it's just not worth it.
The logic is that for the first 2-3 years I will be able to shorten the long
degraded period while a failed disk is being replaced by the vendor.
My current array (7x4TB WD Blacks) left me with little trust in disks.
During the 5 years life of the disks I had 10 replacements, so I now
expect similar future :-(
Regards
Andreas Klauer
Regards,
Eyal
--
Eyal at Home (eyal@xxxxxxxxxxxxxx)
