From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f50.google.com ([209.85.192.50]:38662 "EHLO mail-qg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756223AbaKTUfB (ORCPT ); Thu, 20 Nov 2014 15:35:01 -0500 Received: by mail-qg0-f50.google.com with SMTP id e89so2732966qgf.9 for ; Thu, 20 Nov 2014 12:35:00 -0800 (PST) Message-ID: <546E5066.1040107@ubuntu.com> Date: Thu, 20 Nov 2014 15:34:46 -0500 From: Phillip Susi MIME-Version: 1.0 To: Robert White , Duncan <1i5t5.duncan@cox.net>, linux-btrfs@vger.kernel.org Subject: Re: scrub implies failing drive - smartctl blissfully unaware References: <546AF572.2020101@swiftspirit.co.za> <20141118153526.GS20972@merlins.org> <47FB8035-FEA6-40E1-9672-5BBF92B283A9@colorremedies.com> <546BB2EA.5080809@ubuntu.com> <546CC04F.6040207@ubuntu.com> <546D0609.9040105@pobox.com> <546D0FEA.5000608@ubuntu.com> <546D1AD3.2010206@pobox.com> In-Reply-To: <546D1AD3.2010206@pobox.com> Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 11/19/2014 5:33 PM, Robert White wrote: >> That would be fake raid, not hardware raid. > > The LSI MegaRaid controller people would _love_ to hear more about > your insight into how their battery-backed multi-drive RAID > controller is "fake". You should go work for them. Try the "contact > us" link at the bottom of this page. I'm sure they are waiting for > your insight with baited breath! Forgive me, I should have trimmed the quote a bit more. I was responding specifically to the "many mother boards have hardware RAID support available through the bios" part, not the lsi part. > Odd, my MegaRaid controller takes about fifteen seconds > by-the-clock to initialize and to the integrity check on my single > initialized drive. It is almost certainly spending those 15 seconds on something else, like bootstrapping its firmware code from a slow serial eeprom or waiting for you to press the magic key to enter the bios utility. I would be very surprised to see that time double if you add a second disk. If it does, then they are doing something *very* wrong, and certainly quite different from any other real or fake raid controller I've ever used. > It's amazing that with a fail and retry it would be _faster_... I have no idea what you are talking about here. I said that they aren't going to retry a read that *succeeded* but came back without their magic signature. It isn't like reading it again is going to magically give different results. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) iQEcBAEBAgAGBQJUblBmAAoJEI5FoCIzSKrwFKkIAKNGOGyLrMIcTeV4DQntdbaa NMkjXnWnk6lHeqTyE/pb+l4VgVH8nQwDp8hRCnKNnKHoZbT8LOGFULSmBes+DDmW dxPVDTytUu1AiqB7AyxNJU8213BQCaF0inL7ofZmX95N+0eajuVxOyHIMeokdwUU zLOnXQg0awLkQwk7U6YLAKA4A7HrOEXw4wHt9hPy/yUySMVqCeHYV3tpf7t96guU 0IRctvpwcNvvVtt65I8A4EklR+vCvqEDUZfKyG8WJAeyAdC4UoHT9vZcJAVkiFl+ Y+Mp5wsr1vuo3dYQ1bKO8RvPTB9D9npFyFIlyHEBMJlCHDU43YsNP8hGcu0mKco= =AJ6/ -----END PGP SIGNATURE-----