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On 11/02/2014 13:07, Walter Dnes wrote: |
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> On Tue, Feb 11, 2014 at 07:32:46AM +0200, Alan McKinnon wrote |
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> |
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>> emerge --sync X number of times daily in a cron |
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>> |
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>> emerge -avuND world deliberately and manually as the sysadmin at your |
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>> leisure. |
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>> |
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>> Two different actions in time. |
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> |
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> Assume you sync once a day, and update once a week, the first 6 syncs |
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> would be mostly wasted. Yes, your final sync would be smaller. But |
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> your machine and the server would have to go through the file-comparison |
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> process 7 times, instead of once. |
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> |
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So what? rsync is cheap and doesn't stress the server unduly. |
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It doesn't check every object in the directory tree and stat 179680 |
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files/dirs every time, the whole thing is hashed and it's the hash |
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values that are compared. To compare a directory, rsync only needs to |
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look at the directory inode, if they match on both ends then it's a |
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certainty the files match. It's a *very* efficient system, all done |
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in-memory, your average server can deal with many connections and not |
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even break a sweat. |
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If you want to minimize load, concentrate on making emerge world more |
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efficient so that it takes less than 3 minutes to depgraph on a fast cpu |
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and up to 40 on a slow one. Coupled with overlays, more often than not |
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the portage cache is invalidated so emerge ends up sourcing almost every |
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ebuild file in the tree. |
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--sync is not something worth optimizing if done once a day. At that |
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frequency you are well below the noise floor |
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-- |
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Alan McKinnon |
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alan.mckinnon@×××××.com |
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