Re: [HPDD-discuss] lustre FID-in-dirent backward compatibility
The fid-in-dirent feature is only relevant on the MDT. It does not directly affect the
client or OST, but will affect the performance that the client sees when accessing files
created under 2.x.
There is a noticeable performance improvement (or more specifically no performance
degradation) for 2.x files with this feature enabled. The main reason it is not enabled by
default is that it impacts the ability to downgrade to 1.8 again safely. Once you know you
don't want to downgrade again it is ok to enable it.
Cheers, Andreas
On Feb 6, 2014, at 13:43, "Chris Hunter"
<chris.hunter(a)yale.edu> wrote:
We are in process of upgrading a lustre FS. We currently have the MDS and OSS servers
running 2.1.5 (upgraded from 1.8.9). However our client are still running 1.8.9.
I am trying to clarify if the "FID-in-dirent" feature (ie. tunefs -O dirdata)
is backwards compatible with 1.8.9 clients ?
I have seen a few talks (SC11?) that says it should be. However the 2.x lustre operations
manual at hpdd-intel doesn't *explicitly* say it will work with older clients.
Is there high risk involved enabling "dirdata" when running old 1.8.9 clients
?
Any opinions if there is benefit in using this flag ?
thanks,
chris hunter
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