From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: woes with... mdadm ? Date: Fri, 29 Jan 2010 21:42:59 +1100 Message-ID: <20100129214259.27409fd8@notabene> References: <4B5F6C5D.8020202@ultratux.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4B5F6C5D.8020202@ultratux.net> Sender: linux-raid-owner@vger.kernel.org To: Maarten Cc: linux-raid List-Id: linux-raid.ids On Tue, 26 Jan 2010 23:27:41 +0100 Maarten wrote: > Hi Folks, > > I'm having no end of trouble with a freshly built x86_64 system. After > reboots checksums are corrupted, I cannot add drives back in, etc. I've > downgraded from mdadm 3.0 to 2.6.8 but that doesn't change anything. > First of all, maybe I'm missing something obvious. Does anyone spot an > error in the following ? > It looks to me like you have a very nasty hardware problem somewhere, possibly in a sata controller, but I cannot be sure. You write data out to the disk and read it back in, and find you have slightly different data. This is showing up as a wrong checksum. You results are begin confused by the fact that writes are cached and when you read you might be reading from the device or you might be reading from the cache. I would suggest that you write a known pattern to the device. Flush all caches echo 3 > /proc/sys/vm/drop_caches then read back and compare. That should confirm that it is a device problem.. I cannot think of anything else that would explain your symptoms. NeilBrown