Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 25 Dec 2002 06:15:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 25 Dec 2002 06:15:33 -0500 Received: from m3.azalea.se ([217.75.96.207]:59305 "HELO m3.azalea.se") by vger.kernel.org with SMTP id ; Wed, 25 Dec 2002 06:15:31 -0500 Subject: Alot of DMA errors in 2.4.18, 2.4.20 and 2.5.52 From: Mikael Olenfalk To: linux-kernel@vger.kernel.org Content-Type: text/plain Organization: Netgineers Message-Id: <1040815160.533.6.camel@devcon-x> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.0 Date: 25 Dec 2002 12:19:21 +0100 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4070 Lines: 119 Hi Everybody, I wish you all a nice Christmas and A Happy New Year! Now to the stuff that matters (for me 8) ): I recently bought 4 80G IDE disks which I considered to combine into a software RAID (RAID5). The four discs are connected via a Promise Ultra100 TX2 (driver: PDC202xx, PDC20268 - I believe ;) ). It all works fine for me just that the data throughput (i.e. speed) has been very varying. I had an older 80G IDE disc (yet capable of UDMA5) which I wanted to make a spare disk. This is my configuration: raiddev /dev/md0 raid-level 5 nr-raid-disks 4 nr-spare-disks 1 persistent-superblock 1 parity-algorithm left-symmetric chunk-size 64 ## ALL NEW DISCS :) device /dev/hde raid-disk 0 device /dev/hdf raid-disk 1 device /dev/hdg raid-disk 2 device /dev/hdh raid-disk 3 ## GOOD, OLD, BRAVE DISC ;) device /dev/hdc spare-disk 0 Now to the funny part: For some funny reason, a 2.4.20 kernel refuses to set the DMA-level on the new disks (all connected to a UDMA5-capable Ultra100 TX2 controller) to UDMA5,4,3 and settles it for UDMA2, which is the highest possibility for the OLD onboard-controller (but NOT for the promise card). A recent 2.5.52 gives me :) UDMA5 on the new discs while (correctly) UDMA2 for the old drive. This is generally not a very big problem, I can live 8( with my new fine discs only being used in UDMA2 (instead of 5). After I initialized the array using 'mkraid /dev/md0' I open up 'while true; do clear; cat /proc/mdstat; sleep 1; done' on one terminal to watch the progress. The first try I gave it was (very satisfying) giving me 15MB/sec at the beginning. After about 30-40% the speed fell down to unsatisfying 100-200KB/sec (nothing CPU-intensive running besides raid5d). I have been having problems with the older controller and I was not sure about the throughput of the old drive, therefore I stopped the syncing, stopped the raid and ran five synced (i.e. with a semaphore) bonnie++ processes to benchmark the discs, they all performed likely well (the old one was a little slower at random seeks, but that was indeed expected). I tried the same thing on a 2.4.18 kernel (bf2.4 flavour from Debian SID) but that gave me funny DMA timeout errors (something like DMA timeout func 14 only supported) and kicked out one of (sporadic) my newer drives from the array. I wanted to try a 2.5.x kernel and settled for the newest one: 2.5.52 (vanilla). This wonderful kernel detected the UDMA5 capability of the new drives and the new controller (veeery satisfying =) ) and gave me a throughput of about 20-22MB/sec in the beginning. Sadly the system Ooopsed at 30% percent giving me some DMA errors. I have been wondering if it could be the powersupply, I have a 360W (max load) powersupply, 4 new IBM 80G discs, 1 older 80G SEAGATE, 1 20G MAXTOR. Hmm, there it was again, one of my new drives got kicked out of the array before the initial sync was ready. The errors was (2.4.20): webber kernel: hdg: dma_intr: status=0x51 webber kernel: hdg: end_request: I/O error, dev 22:00 (hdg) sector 58033224 webber kernel: hdg: dma_intr: status=0x51 webber kernel: hdg: dma_intr: error=0x40 LBAsect=58033238, sector=58033232 webber kernel: end_request: I/O error, dev 22:00 (hdg), sector 58033232 Hmm, what could it be, this didn't happen while running bonnie++ :( Any help will be appreciated, Regards, Mikael -- Mikael Olenfalk Netgineers - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/