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On 23:53 Tue 26 Oct , Robin H. Johnson wrote: |
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> On Tue, Oct 26, 2010 at 07:15:46PM +0000, Robin H. Johnson wrote: |
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> > Repo layout |
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> > * Natural option (seems to be used by most projects) is one package per repo |
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> > * Main problems: how to manage initial clones, updates, package moves, category moves |
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> > * The "repo" tool written for Android can handle most of this |
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> > * Renaming packages a problem (requires admin participation) |
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> > * Average 1-2/week over the past few years |
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> > * Moving packages between categories can be done by committers |
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> The other major problem with splitting the repo, is that the overhead |
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> that will be imposed by it. This got lost during the talks, but I've |
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> followed up with warthog9, and the size is going to hurt. |
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> |
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> In an attempt to explain that better, I've laid out below, the (inode) |
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> overhead costs per checkouts in each VCS, in a variant of O-notation. |
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> d = number of directories, f = number of files, r = number of |
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> repositories. |
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> CVS: O(3d) |
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> SVN: O(8d + 2f) |
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> Git: O(35r) |
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Very interesting numbers, Robin! |
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By making the (simplistic?) assumption that the above O(foo) is really |
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=foo, I attempted to calculate the direct comparisons of disk space that |
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follow from the info you provided. |
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In that case, SVN, Hg and Git all use at least 4x the space of CVS for |
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per-package, and SVN doesn't even differentiate between one big repo or |
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per-package. A repo-per-package model in Git would be nearly equivalent |
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in inode overhead to using SVN. Is that really a bad thing? |
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With 4K blocks, that works out at roughly 500 MB (CVS) to 2 GB (SVN, |
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Git) of inode overhead. I have a hard time imagining people so hard up |
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for disk space that they can fit the whole git repo but can't find |
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another 1.5 GB. |
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|
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Based on my current git conversion with a pack size of 1.7 GB, I suppose |
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that means the total repo in a git world could vary from ~2 GB all the |
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way up to ~4 GB. |
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|
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-- |
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Thanks, |
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Donnie |
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|
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Donnie Berkholz |
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Sr. Developer, Gentoo Linux |
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Blog: http://dberkholz.wordpress.com |
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