Ominous smartd messages ....

William A. Mahaffey III wam at
Wed Aug 3 20:29:20 UTC 2016

On 08/03/16 15:19, Matthew Seaman wrote:
> On 03/08/2016 20:13, William A. Mahaffey III wrote:
>> What does this mean ?
> That there's a bad spot on the disk, which may also mean that you've got
> a corrupted filesystem -- depends if the bad spot was in use by zfs or
> not.  'zpool scrub' should tell you if the filesystem is corrupted.

Can I do that 'zpool scrub' live ?

> Time to replace the drive.  You should be able to convert the vdev that
> contains the failing drive into a mirror temporarily, and sync the data
> without downtime beyond maybe a few reboots to install the new disk
> (assuming you have space to plug the new drive in without unplugging any
> of the old ones).  Failing that, you're going to need to rebuild the
> zpool from scratch and restore your data from backup.

No spare SATA slots :-/ ....

> Also, the fact that you have how ever many terabytes of data with no
> resilience just makes me feel on edge -- and it's not even my data.
> Strongly recommend rebuilding your zpool as a RAIDZ of 8 drives -- yes,
> you'll end up with less usable space, but you and your data will survive
> failure of a drive and a 'zpool scrub' will be able to fix things even
> if a bad spot on one drive has scrambled some of your data.

I was/am already thinking along those lines, w/ 1 complication. I have 
another box (NetBSD 6.1.5) w/ a RAID5 that I wound up building w/ 
mis-aligned disk/RAID blocks in spite of a fair amount of effort to 
avoid that. I/O writes are horrible, 15-20 MB/s. My understanding is 
that RAIDZn is like RAID5 in many ways & that you always want 2^n+1 
(3,5,9, ...) drives in a RAID5 to mitigate those misalignments, 
presumably in a RAIDZ also. Is that so w/ RAIDZ as well ? If so, I lose 
more than a small amount of total storage, which is why I went as I did 
when I built the box whenever that was.


	William A. Mahaffey III


	"The M1 Garand is without doubt the finest implement of war
	 ever devised by man."
                            -- Gen. George S. Patton Jr.

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