From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wols Lists Subject: Re: RAID6 - CPU At 100% Usage After Reassembly Date: Tue, 11 Oct 2016 10:23:31 +0100 Message-ID: <57FCAF93.9040305@youngman.org.uk> References: <20160913174352.GA43576@kernel.org> <20161006235530.GA109312@kernel.org> <63380999-4291-97e9-41e4-363903e5c07b@fnarfbargle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <63380999-4291-97e9-41e4-363903e5c07b@fnarfbargle.com> Sender: linux-raid-owner@vger.kernel.org To: Brad Campbell , Francisco Parada Cc: mdraid List-Id: linux-raid.ids On 11/10/16 04:53, Brad Campbell wrote: > On 07/10/16 19:23, Francisco Parada wrote: > >> issue with the model drives that I'm using. I've got WD 3TB Green >> EZRX drives, which I recently found out via the RAID Wiki, that they >> didn't have error correction (after I spent over a thousand dollars on >> the drives in 3 years) ... Had I known better, I would have opted for >> different models. > > That's not entirely true. EZRX drives have just as much "error > correction" as any other drive. What they don't have is the ability to > rapidly terminate their error correction (WD call it Time Limited Error > Recovery or TLER). Nothing wrong with that provided your OS storage > stack timeouts are set appropriately, as without that the drives will > take longer to process the error than the OS will wait and things get > ugly resulting in drives kicked from arrays. > > Sure, they're not the best drives for the job, and buying new I wouldn't > recommend them; but disable periodic head parking and spindown, set the > timeouts appropriately and they'll do the job until they need replacing. > I've put your timeout fix script on the wiki :-) It strikes me this would be a good addition too - I could probably manage something of the sort, but do you or anyone have the code to detect a green, and do that "disable parking and spindown"? It's a pain, but having a script that deals with all known and common issues with drives is probably a good thing. I ought to go through that script and comment it heavily - I know the experts will say "Why?" :-) but (although I may be a guru elsewhere) this is an area I'm learning - hopefully fast - and comments are helpful when reading code :-) They can always be deleted in production. Cheers, Wol