Re: ZFS + mysql appears to be killing my SSD's
Date: Mon, 05 Jul 2021 14:51:14 UTC
On Mon, Jul 5, 2021 at 8:31 AM Pete French <petefrench@ingresso.co.uk> wrote: > > > 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 > unfortunately. > > > 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... > > -pete. > If you're using 4K sectors anyway, then GELI does not create any extra write amplification. But if you're extra paranoid and you use the "-T" option to "geli attach", then GELI will block TRIM commands. That could hurt SSD lifetime. But I don't think "-T" is the default. You are using 4K sectors, right? ZFS's ashift is set to 12? -Alan