From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from atl4mhob05.myregisteredsite.com ([209.17.115.43]:45315 "EHLO atl4mhob05.myregisteredsite.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751496Ab3EEOPq (ORCPT ); Sun, 5 May 2013 10:15:46 -0400 Received: from mailpod1.hostingplatform.com ([10.30.71.117]) by atl4mhob05.myregisteredsite.com (8.14.4/8.14.4) with ESMTP id r45EFiTi012920 for ; Sun, 5 May 2013 10:15:44 -0400 Message-ID: <51866994.8010107@chinilu.com> Date: Sun, 05 May 2013 07:15:48 -0700 From: George Mitchell Reply-To: george@chinilu.com MIME-Version: 1.0 To: Martin Steigerwald CC: linux-btrfs@vger.kernel.org Subject: Re: Scrub CPU usage ... References: <518555FF.4020704@chinilu.com> <2221106.SQ983GtkxQ@merkaba> In-Reply-To: <2221106.SQ983GtkxQ@merkaba> Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 05/05/2013 02:22 AM, Martin Steigerwald wrote: > Hi George! > > Am Samstag, 4. Mai 2013, 11:39:59 schrieb George Mitchell: >> the next update. I am using btrfs raid 1 across five 500GB Seagate >> nearline drives and btrfs single on a Seagate 4TB backup drive. I am >> absolutely delighted with how this system is working. This is my >> primary day in and day out system. I have to date hard crashed this >> system at least three times without sustaining any apparent damage to >> the filesystems. Perhaps I have just been extremely lucky, but it seems >> like most of the major holes have been closed at this point. Actually I >> have only two significant issues currently with btrfs. > Are you aware that BTRFS RAID-1 works differently than block based RAID? BTRFS > will only be holding two copies of every data or metadata chunk on two > different drives, regardless how many drives you use. So only one drive may > fail. > > Well, I think you will have notices with df output for the filesystem, but I > thought I mention it, just in case. > > Thanks, Yes indeed! I was aware of this from the beginning. All I am looking for is duplication across hardware. The advantage of more than two drives is that in case you lose a drive, you don't end up losing a lot of space, and you are much less likely to end up in an unduplicated state for a significant amount of time. But thanks for your thoughts! What I am NOT missing about the old 3ware card is the resyncs. I used to spend half a day doing drive resyncs when a drive dropped out for some reason. Hardware RAID is great when it works, but I much prefer btrfs. Software RAID has its own problems. Its gotten better I hear, but when I used it for a long time, I was a pain. But both forms of block RAID saved me from ever losing data. - George