Re: ZFS + mysql appears to be killing my SSD's

From: Pete French <>
Date: Mon, 05 Jul 2021 14:30:43 UTC

On 05/07/2021 14:37, Stefan Esser wrote:
> Hi Pete,
> have you checked the drive state and statistics with smartctl?

Hi, thanks for the reply - yes, I did check the statistics, and they 
dont make a lot of sense. I was just looking at them again in fact.

So, one of the machines that we chnaged a drive on when this first 
started, which was 4 weeks ago.

root@telehouse04:/home/webadmin # smartctl -a /dev/ada0 | grep Perc
169 Remaining_Lifetime_Perc 0x0000   082   082   000    Old_age 
Offline      -       82
root@telehouse04:/home/webadmin # smartctl -a /dev/ada1 | grep Perc
202 Percent_Lifetime_Remain 0x0030   100   100   001    Old_age 
Offline      -       0

Now, from that you might think the 2nd drive was the one changes, but 
no. Its the first one, which is now at 82% lifetime remaining! The other 
druve, still at 100%, has been in there a year. The drives are different 
manufacturers, which makes comparing most of the numbers tricky 

Am now even more worried than when I sent the first email - if that 18% 
is accurate then I am going to be doing this again in another 4 months, 
and thats not sustainable. It also looks as if this problem has got a 
lot worse recently. Though I wasnt looking at the numbers before, only 
noticing tyhe failurses. If I look at 'Percentage Used Endurance 
Indicator' isntead of the 'Percent_Lifetime_Remain' value then I see 
some of those well over 200%. That value is, on the newer drives, 100 
minus the 'Percent_Lifetime_Remain' value, so I guess they ahve the same 
underlying metric.

I didnt mention in my original email, but I am encrypting these with 
geli. Does geli do any write amplification at all ? That might explain 
the high write volumes...