Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932226AbXBWMm2 (ORCPT ); Fri, 23 Feb 2007 07:42:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932304AbXBWMm2 (ORCPT ); Fri, 23 Feb 2007 07:42:28 -0500 Received: from lucidpixels.com ([75.144.35.66]:34955 "EHLO lucidpixels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932226AbXBWMm1 (ORCPT ); Fri, 23 Feb 2007 07:42:27 -0500 Date: Fri, 23 Feb 2007 07:42:26 -0500 (EST) From: Justin Piszcz X-X-Sender: jpiszcz@p34.internal.lan To: Jason Rainforest cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: 2.6.20: stripe_cache_size goes boom with 32mb In-Reply-To: <1172234460.4419.7.camel@merlin> Message-ID: References: <1172234460.4419.7.camel@merlin> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1819 Lines: 55 I have 2GB On this machine. For me, 8192 seems to be the sweet spot, I will probably keep it at 8mb. On Fri, 23 Feb 2007, Jason Rainforest wrote: > Hi Justin, > > I'm not a RAID or kernel developer, but .. do you have enough RAM to > support a 32mb stripe_cache_size?! Here on my 7*250Gb SW RAID5 array, > decreasing a stripe_cache_size of 8192 to 4096 frees up no less than > 120mb of RAM. Using that as a calculation tool, a 32mb stripe_cache_size > would require approximately 960mb of RAM! My RAID box only has 1Gb of > RAM, so I'm not game to test such a thing. Others on these lists would > definitely have a good idea on what's happening :-) > > Cheers, > Jason > > > On Fri, 2007-02-23 at 06:41 -0500, Justin Piszcz wrote: >> Each of these are averaged over three runs with 6 SATA disks in a SW RAID >> 5 configuration: >> >> (dd if=/dev/zero of=file_1 bs=1M count=2000) >> >> 128k_stripe: 69.2MB/s >> 256k_stripe: 105.3MB/s >> 512k_stripe: 142.0MB/s >> 1024k_stripe: 144.6MB/s >> 2048k_stripe: 208.3MB/s >> 4096k_stripe: 223.6MB/s >> 8192k_stripe: 226.0MB/s >> 16384k_stripe: 215.0MB/s >> >> When I tried a 32768k stripe, this happened: >> p34:~# echo 32768 > /sys/block/md4/md/stripe_cache_size >> Connection to p34 closed >> >> I was able to Alt-SysRQ+b but I could not access the console/X/etc, it >> appeared to be frozen. >> >> FYI. >> >> Justin. >> >> - >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > - 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/