[gpfsug-discuss] Online data migration tool

[Stephen Ulmer]

About five years ago (I think) Apple slipped a volume manager[1] in on the unsuspecting. :) If you have a Mac, you might have noticed that the mount type/pattern changed with Lion. CoreStorage was the beginning of building the infrastructure to change a million(?) Macs and several hundred million iPhones and iPads under the users’ noses. :)

Has anyone seen list of the features that would require the on-disk upgrade? If there isn’t one yet, I think that the biggest failing is not not publishing it — the natives are restless and it’s not like IBM wouldn’t know...

[1] This is what Apple calls it. If you’ve ever used AIX or Linux you’ll just chuckle when you look at the limitations.

-- 
Stephen



> On Nov 29, 2017, at 11:51 AM, Buterbaugh, Kevin L <Kevin.Buterbaugh at Vanderbilt.Edu> wrote:
> 
> Hi All,
> 
> Well, actually a year ago we started the process of doing pretty much what Richard describes below … the exception being that we rsync’d data over to the new filesystem group by group.  It was no fun but it worked.  And now GPFS (and it will always be GPFS … it will never be Spectrum Scale) version 5 is coming and there are compelling reasons to want to do the same thing over again … despite the pain.
> 
> Having said all that, I think it would be interesting to have someone from IBM give an explanation of why Apple can migrate millions of devices to a new filesystem with 99.999999% of the users never even knowing they did it … but IBM can’t provide a way to migrate to a new filesystem “in place.”
> 
> And to be fair to IBM, they do ship AIX with root having a password and Apple doesn’t, so we all have our strengths and weaknesses!  ;-)
> 
> Kevin
> —
> Kevin Buterbaugh - Senior System Administrator
> Vanderbilt University - Advanced Computing Center for Research and Education
> Kevin.Buterbaugh at vanderbilt.edu - (615)875-9633
> 
>> On Nov 29, 2017, at 10:39 AM, Sobey, Richard A <r.sobey at imperial.ac.uk> wrote:
>> 
>> Could we utilise free capacity in the existing filesystem and empty NSDs, create a new FS and AFM migrate data in stages? Terribly long winded and frought with danger and peril... do not pass go... ah, answered my own question.
>> 
>> 😊
>> 
>> Richard
>> 
>> -----Original Message-----
>> From: gpfsug-discuss-bounces at spectrumscale.org [mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Jonathan Buzzard
>> Sent: 29 November 2017 16:35
>> To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
>> Subject: Re: [gpfsug-discuss] Online data migration tool
>> 
>> On Wed, 2017-11-29 at 11:00 -0500, Yugendra Guvvala wrote:
>>> Hi,
>>> 
>>> I am trying to understand the technical challenges to migrate to GPFS
>>> 5.0 from GPFS 4.3. We currently run GPFS 4.3 and i was all exited to 
>>> see 5.0 release and hear about some promising features available. But 
>>> not sure about complexity involved to migrate.
>>> 
>> 
>> Oh that's simple. You copy all your data somewhere else (good luck if you happen to have a few hundred TB or maybe a PB or more) then reformat your files system with the new disk format then restore all your data to your shiny new file system.
>> 
>> Over the years there have been a number of these "reformats" to get all the new shiny features, which is the cause of the grumbles because it is not funny and most people don't have the disk space to just hold another copy of the data, and even if they did it is extremely disruptive.
>> 
>> JAB.
>> 
>> -- 
>> Jonathan A. Buzzard                         Tel: +44141-5483420
>> HPC System Administrator, ARCHIE-WeSt.
>> University of Strathclyde, John Anderson Building, Glasgow. G4 0NG
> 
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