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From Jonathan Disher <jdis...@parad.net>
Subject Re: our experiences with various filesystems and tuning options
Date Tue, 10 May 2011 11:26:24 GMT
In a previous life, I've had extreme problems with XFS, including kernel panics and data loss
under high load.

Those were database servers, not Hadoop nodes, and it was a few years ago.  But, ext3/ext4
seems to be stable enough, and it's more widely supported, so it's my preference.

-j

On May 10, 2011, at 3:59 AM, Rita wrote:

> I keep asking because I wasn't able to use a XFS filesystem larger than 3-4TB. If the
XFS file system is larger than 4TB hdfs won't recognize the space. I am on a 64bit RHEL 5.3
host.
> 
> 
> On Tue, May 10, 2011 at 6:30 AM, Will Maier <wcmaier@hep.wisc.edu> wrote:
> On Tue, May 10, 2011 at 12:03:09AM -0400, Rita wrote:
> > what filesystem are they using and what is the size of each filesystem?
> 
> It sounds nuts, but each disk has its own ext3 filesystem. Beyond switching to
> the deadline IO scheduler, we haven't done much tuning/tweaking. A script runs
> every ten minutes to test all of the data mounts and reconfigure hdfs-site.xml
> and restart the datanode if necessary. So far, this approach has allowed us to
> avoid loss of space to RAID without correlating the risk of disk failure by
> building larger RAID0s.
> 
> In the future, we expect to deprecate the script and rely on the datanode process
> itself to handle missing/failing disks.
> 
> --
> 
> Will Maier - UW High Energy Physics
> cel: 608.438.6162
> tel: 608.263.9692
> web: http://www.hep.wisc.edu/~wcmaier/
> 
> 
> 
> -- 
> --- Get your facts first, then you can distort them as you please.--


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