From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: Linux Software RAID is really RAID? Date: Tue, 03 Jul 2007 19:08:56 -0400 Message-ID: <468AD708.2010806@rtr.ca> References: <46815C3F.6090204@wasp.net.au> <468A05A4.60006@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-ide-owner@vger.kernel.org To: Johny Mail list Cc: Tejun Heo , Brad Campbell , linux-raid@vger.kernel.org, linux-ide@vger.kernel.org List-Id: linux-raid.ids Johny Mail list wrote: > 2007/7/3, Tejun Heo : >> Brad Campbell wrote: >> > Johny Mail list wrote: >> >> Hello list, >> >> I have a little question about software RAID on Linux. >> >> I have installed Software Raid on all my SC1425 servers DELL by >> >> believing that the md raid was a strong driver. >> >> And recently i make some test on a server and try to view if the RAID >> >> hard drive power failure work fine, so i power up my server and after >> >> booting and the prompt appear I disconnected the power cable of my >> >> SATA hard drive. Normaly the MD should eleminate the failure hard >> >> drive of the logical drive it build, and the server continue to work >> >> fine like nothing happen. Oddly the server stop to respond and i get >> >> this messages : >> >> ata4.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x2 frozen >> >> ata4.00: cmd e7/00:00:00:00:00/00:00:00:00:00/a0 tag 0 cdb 0x0 data 0 >> >> res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 >> (timeout) >> >> ata4: port is slow to respond, please be patient (Status 0xd0) >> >> ata4: port failed to respond (30sec, Status 0xd0) >> >> ata4: soft resetting port >> >> >> >> After that my system is frozen. >> >> How hard is it frozen? Can you blink the Numlock LED? I believe he said it was ICH5 (different post/thread). My observation on ICH5 is that if one unplugs a drive, then the chipset/cpu locks up hard when toggling SRST in the EH code. Specifically, it locks up at the instruction which restores SRST back to the non-asserted state, which likely corresponds to the chipset finally actually sending a FIS to the drive. A hard(ware) lockup, not software. That's why Intel says ICH5 doesn't do hotplug. Cheers