Date: Wed, 13 Dec 2017 13:25:20 +0200 From: Daniel Kalchev <daniel@digsys.bg> To: Freddie Cash <fjwcash@gmail.com> Cc: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.cn85.dnsmgr.net>, "O. Hartmann" <ohartmann@walstatt.org>, FreeBSD CURRENT <freebsd-current@freebsd.org>, Alan Somers <asomers@freebsd.org> Subject: Re: SMART: disk problems on RAIDZ1 pool: (ada6:ahcich6:0:0:0): CAM status: ATA Status Error Message-ID: <B925DA94-D0D2-43FE-AB13-7B0A3F9E9613@digsys.bg> In-Reply-To: <CAOjFWZ5QePzNoh6=_Wv2yVL2LbmuKkuNGqhMWWcehMnFnJFwWQ@mail.gmail.com> References: <20171212231858.294a2cb5@thor.intern.walstatt.dynvpn.de> <201712122255.vBCMtnfZ088889@pdx.rh.CN85.dnsmgr.net> <CAOjFWZ5QePzNoh6=_Wv2yVL2LbmuKkuNGqhMWWcehMnFnJFwWQ@mail.gmail.com>
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> On 13 Dec 2017, at 1:26, Freddie Cash <fjwcash@gmail.com> wrote: >=20 > On Tue, Dec 12, 2017 at 2:55 PM, Rodney W. Grimes < > freebsd-rwg@pdx.rh.cn85.dnsmgr.net> wrote: >=20 >> Hum, just noticed this. 25k hours power on, 2M load cycles, this is >> very hard on a hard drive. Your drive is going into power save mode >> and unloading the heads. Infact at a rate of 81 times per hour? >> Oh, I can not believe that. Either way we need to get this stopped, >> it shall wear your drives out. >>=20 >=20 > =E2=80=8BBelieve it. :) The WD Green drives have a head parking = timeout of 15 > seconds, and no way to disable that anymore. You used to be able to = boot > into DOS and run the tler.exe program from WD to disable the = auto-parking > feature, but they removed that ability fairly quickly. >=20 > The Green drives are meant to be used in systems that spend most of = their > time idle. Trying to use them in an always-on RAID array is just = asking > for trouble. They are only warrantied for a couple hundred thousand = head > parkings or something ridiculous like that. 2 million puts it way out = of > the warranty coverage. :( >=20 > We had 24 of them in a ZFS pool back when they were first released as = they > were very inexpensive. They lead to more downtime and replacement = costs > than any other drive we've used since (or even before). Just don't = use > them in any kind of RAID array or always-on system. >=20 In order to handle drives like this and in general to get rid of load = cycles, I use smartd on all my ZFS pools with this piece of config: DEVICESCAN -a -o off -e apm,off=20 Might not be the best solution, but as it is activated during boot, = S.M.A.R.T. attribute 193 Load_Cycle_Count does not increase anymore. Not = fan of WD drives, but have few tens of them=E2=80=A6 all of them = =E2=80=9Cbehave=E2=80=9D in some way or another. For the original question, if I do not have spare disk to replace, on a = raidz1/raidz2 pool I would typically do: zpool offline poolname disk dd if=3D/dev/zero of=3D/dev/disk bs=3D1m zpool replace poolname disk This effectively fills the disk with zeros, forcing any suspected = unreadable blocks to be replaced. After this operation, no more pending = blocks etc. But, on large drives/pools requires few days to complete = (the last part). Over the years, I have used this procedure on many = drives, sometimes more than once on the same drive and that posponed = having to replace the drive and the annoying S.M.A.R.T. message: which = by itself might not be major problem, but better not have the logs = filled with warnings all the time. I feel more confident doing this on raidz2 vdevs anyway.. If I had spare disk and spare port, just zpool replace poolname disk Daniel=
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