Messages in this thread | | | Date | Fri, 23 Feb 2007 07:42:26 -0500 (EST) | From | Justin Piszcz <> | Subject | Re: 2.6.20: stripe_cache_size goes boom with 32mb |
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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/
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