Thanks, Nikhil. Most of that was consistent with my understnading, however I was under the impression that the >32 subblocks code is required to achieve the touted 50k file creates/second that Sven has talked about a bunch of times:
http://files.gpfsug.org/presentations/2017/Manchester/08_Research_Topics.pdf http://files.gpfsug.org/presentations/2017/Ehningen/31_-_SSUG17DE_-_Sven_Oehme_-_News_from_Research.pdf http://files.gpfsug.org/presentations/2016/SC16/12_-_Sven_Oehme_Dean_Hildebrand_-_News_from_IBM_Research.pdf from those presentations regarding 32 subblocks: "It has a significant performance penalty for small files in large block size filesystems" although I'm not clear on the specific definition of "large". Many filesystems I encounter only have a 1M block size so it may not matter there, although that same presentation clearly shows the benefit of larger block sizes which is yet *another* thing for which a migration tool would be helpful. -Aaron On Wed, Nov 29, 2017 at 2:08 PM, Nikhil Khandelwal <[email protected]> wrote: > Hi, > > I would like to clarify migration path to 5.0.0 from 4.X.X clusters. For > all Spectrum Scale clusters that are currently at 4.X.X, it is possible to > migrate to 5.0.0 with no offline data migration and no need to move data. > Once these clusters are at 5.0.0, they will benefit from the performance > improvements, new features (such as file audit logging), and various > enhancements that are included in 5.0.0. > > That being said, there is one enhancement that will not be applied to > these clusters, and that is the increased number of sub-blocks per block > for small file allocation. This means that for file systems with a large > block size and a lot of small files, the overall space utilization will be > the same it currently is in 4.X.X. Since file systems created at 4.X.X and > earlier used a block size that kept this allocation in mind, there should > be very little impact on existing file systems. > > Outside of that one particular function, the remainder of the performance > improvements, metadata improvements, updated compatibility, new > functionality, and all of the other enhancements will be immediately > available to you once you complete the upgrade to 5.0.0 -- with no need to > reformat, move data, or take your data offline. > > I hope that clarifies things a little and makes the upgrade path more > accessible. > > Please let me know if there are any other questions or concerns. > > Thank you, > Nikhil Khandelwal > Spectrum Scale Development > Client Adoption > > _______________________________________________ > gpfsug-discuss mailing list > gpfsug-discuss at spectrumscale.org > http://gpfsug.org/mailman/listinfo/gpfsug-discuss > >
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