From mboxrd@z Thu Jan 1 00:00:00 1970 From: Justin Piszcz Subject: Re: 2.6.20: stripe_cache_size goes boom with 32mb Date: Fri, 23 Feb 2007 07:42:26 -0500 (EST) Message-ID: References: <1172234460.4419.7.camel@merlin> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Return-path: In-Reply-To: <1172234460.4419.7.camel@merlin> Sender: linux-raid-owner@vger.kernel.org To: Jason Rainforest Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org List-Id: linux-raid.ids 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 >