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     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/e4rat/description.txt	Mon Apr 06 09:22:36 2020 +0100
     1.3 @@ -0,0 +1,49 @@
     1.4 +e4rat reduces disk access times through physical file reallocation. It is based
     1.5 +on the online defragmentation ioctl EXT4_IOC_MOVE_EXT from the ext4 filesystem,
     1.6 +which was introduced in Linux Kernel 2.6.31. Therefore, other filesystem types
     1.7 +or earlier versions of extended filesystems are not supported.
     1.8 +
     1.9 +e4rat consists of three binaries. The first is e4rat-collect. Its purpose is to
    1.10 +gather relevant files by monitoring file accesses during an application startup.
    1.11 +The generated file list is the fundament of the second step. With the second
    1.12 +step, e4rat-realloc, files are placed physically in a row on disk.
    1.13 +The reallocation of the files' content yields a higher disk transfer rate which
    1.14 +accelerates program start processes.
    1.15 +
    1.16 +Third, you can also read-ahead files to gain a higher cache hit rate.
    1.17 +e4rat-preload transfers files into memory in parallel to program startup.
    1.18 +
    1.19 +Because a file consists of file content and its I-Node information the
    1.20 +preloading process is divided into two steps. First, it reads the I-Nodes'
    1.21 +information which are still spread over the entire filesystem. In the second
    1.22 +step, the files' content is read without causing any disk seeks.
    1.23 +
    1.24 +For more information see: e4rat-collect(8), e4rat-realloc(8), e4rat-preload(8)
    1.25 +                          and e4rat.conf(5).
    1.26 +
    1.27 +
    1.28 +SAMPLE USAGE: Accelerate the boot process
    1.29 +-------------
    1.30 +
    1.31 +Run e4rat-collect as init process through adding following line to Kernel
    1.32 +parameters:
    1.33 +
    1.34 +    init=/sbin/e4rat-collect
    1.35 +
    1.36 +After e4rat-collect has terminated the generated file list is stored at:
    1.37 +
    1.38 +    /var/lib/e4rat/startup.log
    1.39 +
    1.40 +Before reallocating boot files it is recommaned to switch to runlevel 1 to stop
    1.41 +most of all running proceses to gain write access to the process binary file:
    1.42 +
    1.43 +    init 1
    1.44 +
    1.45 +Reallocating boot files:
    1.46 +
    1.47 +    e4rat-realloc  /var/lib/e4rat/startup.log
    1.48 +
    1.49 +To start e4rat-preload as initial process append following to kernel your
    1.50 +parameters:
    1.51 +
    1.52 +    init=/sbin/e4rat-preload