Date: Wed, 3 Aug 2016 15:34:47 -0453.75 From: "William A. Mahaffey III" <wam@hiwaay.net> To: freebsd-questions@freebsd.org Subject: Re: Ominous smartd messages .... Message-ID: <e622244a-7836-068d-0554-1898689531a4@hiwaay.net> In-Reply-To: <4b35b969-606b-9084-5ce3-688eddfc5e70@FreeBSD.org> References: <e5a65f8a-27a0-65e7-42db-28bef824e0c0@hiwaay.net> <020caa94-b329-d5a6-5bd4-bfcc575c039f@freebsd.org> <b20550ac-1637-07d4-20dc-7cdc3a5173a9@hiwaay.net> <4b35b969-606b-9084-5ce3-688eddfc5e70@FreeBSD.org>
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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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