Changes between Version 1 and Version 2 of DiagnosingSluggishness


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Timestamp:
Oct 19, 2012, 3:50:00 PM (8 years ago)
Author:
Daniel Kahn Gillmor
Comment:

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  • DiagnosingSluggishness

    v1 v2  
    8989 * the amount of `memory` allocated to buffers (`buff`) and `cache` drop precipitously -- buffering and caching are two performance-optimizing ways that the kernel makes use of memory that is otherwise unallocated.  They speed up your use of the machine without you asking them to do anything concretely, but they are not strictly required to make the computer work correctly.  So when memory gets tight, the kernel reclaims the RAM it was using for buffers and caches to try to accommodate the new requirements coming from the user.
    9090
    91 == Disks (aka "I/O") ==
     91== Disks (aka "storage" or "I/O") ==
    9292
    9393There are really two kinds of resources you can exhaust related to disks, but only one of them typically results in the sluggishness this page attempts to diagnose.  I'll get the other one out of the way first:
    9494
    95 === Disk Space (capacity) ===
     95=== Disk Space (storage capacity) ===
    9696
    9797This is the form of disk resource people are most used to seeing exhausted.  You get messages like "cannot save file, disk is full" from your programs, or you get weird misbehaviors or system failures -- services being unable to log, mail transfer agents bouncing mail, etc.