[gpfsug-discuss] Using AFM to migrate files. (Peter Childs) (Peter Childs) - URL encoding for pathnames

[Venkateswara R Puvvada]

Loic,

It is good to hear that migration is completed. Did you find any prefetch 
errors in mmfs.log for the files which are different between cache and 
home ? Not all errors are logged, there is a plan to generate the list of 
read failed file names after prefetch completion.

Informaion about files moving to .ptrash is documented @

http://www.ibm.com/support/knowledgecenter/STXKQY_4.2.1/com.ibm.spectrum.scale.v4r21.doc/bl1ins_internaldirectoriesAFM.htm

~Venkat (vpuvvada at in.ibm.com)



From:   Loic Tortay <tortay at cc.in2p3.fr>
To:     gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Date:   10/24/2016 10:20 PM
Subject:        Re: [gpfsug-discuss] Using AFM to migrate files. (Peter 
Childs) (Peter Childs) - URL encoding for pathnames
Sent by:        gpfsug-discuss-bounces at spectrumscale.org



On 10/24/2016 11:44 AM, Venkateswara R Puvvada wrote:
> 
> mmafmctl prefecth expects encoded list file, and it is not documented 
> correctly.  Issues like memory leak, file descriptor leak, and fileset 
> going into Unmounted state were fixed in later releases (4.2.1/4.2.2). 
All 
> your points are correct with respect to AFM migration. There is manual 
> intervention required. Also prefetch does not give list of files which 
> were failed during data read. Users need to run policy to find all 
> uncached files today.
> 
Hello,
For the record, I have completed today my AFM migration of a filesystem
with 100 million files. Users are now accessing the new filesystem.

After disabling user access and a last "prefetch", the AFM filesets were
converted to independent filesets.
Less than 600 files were then found to be different between the "home"
and the "cache" filesystems with a metadata comparison (I just copied
the files from the old filesystem to the new one).
I have compared the MD5 of a few thousand randomly selected files and
found no differences between the "home" and the "cache" filesystems.
I expect the users to let us know if they find something different (they
have been instructed to do so). We'll keep the "home" filesystem around
for some time, just in case there is a problem.

Maybe something else that should be mentionned in the documentation is
what to do with the ".ptrash" directories after the AFM filesets have
been converted. I removed them since they contained files that had
clearly been deleted by the users.


Loïc.
-- 
|       Loïc Tortay <tortay at cc.in2p3.fr> - IN2P3 Computing Centre      |
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