wok-next diff e4rat/description.txt @ rev 20889
Check Repology info from y* to z* packages: complete
author | Aleksej Bobylev <al.bobylev@gmail.com> |
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date | Sun Jul 15 10:27:39 2018 +0300 (2018-07-15) |
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1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 1.2 +++ b/e4rat/description.txt Sun Jul 15 10:27:39 2018 +0300 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