Messages in this thread | | | Date | Mon, 22 May 2006 19:30:37 -0300 | From | "Matheus Izvekov" <> | Subject | Re: tuning for large files in xfs |
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On 5/22/06, fitzboy <fitzboy@iparadigms.com> wrote: > I've got a very large (2TB) proprietary database that is kept on an XFS > partition under a debian 2.6.8 kernel. It seemed to work well, until I > recently did some of my own tests and found that the performance should > be better then it is... > > basically, treat the database as just a bunch of random seeks. The XFS > partition is sitting on top of a SCSI array (Dell PowerVault) which has > 13+1 disks in a RAID5, stripe size=64k. I have done a number of tests > that mimic my app's accesses and realized that I want the inode to be > as large as possible (which in an intel box is only 2k), played with su > and sw and got those to 64k and 13... and performance got better. > > BUT... here is what I need to understand, the filesize has a drastic > effect on performance. If I am doing random reads from a 20GB file > (system only has 2GB ram, so caching is not a factor), I get > performance about where I want it to be: about 5.7 - 6ms per block. But > if that file is 2TB then the time almost doubles, to 11ms. Why is this? > No other factors changed, only the filesize. > > Another note, on this partition there is no other file then this one > file. >
Why use a flesystem with just one file?? Why not use the device node of the partition directly? - 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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