libeatmydata
============
An LD_PRELOAD library that disables all forms of writing data safely to disk.
fsync() becomes a NO-OP, O_SYNC is removed etc.
The idea is to use in testing to get faster test runs where real durability is
not required.
***DO NOT*** use libeatmydata on software where you care about what it stores. It's called lib***EAT-MY-DATA*** for a *reason*.
see http://www.flamingspork.com/projects/libeatmydata
Usage
-----
```
eatmydata foo
```
Performance Improvements
------------------------
When running part of the MySQL test suite in 2007 on my laptop:
```
TEST RESULT TIME (ms) TIME (with libeatmydata)
----------------------------------------------------------------------------------
main.innodb-lock [ pass ] 4523 4323
main.innodb-replace [ pass ] 102 56
main.innodb-ucs2 [ pass ] 5786 1084
main.innodb [ pass ] 78306 24900
main.innodb_gis [ pass ] 2647 1544
main.innodb_mysql [ pass ] 86810 68579
main.innodb_notembedded [ pass ] 198 150
main.innodb_timeout_rollback [ pass ] 2990 2750
main.innodb_trx_weight [ pass ] 1608 841
---------------------------------------------------------------
Stopping All Servers
All 9 tests were successful.
The servers were restarted 7 times
WITHOUT: Spent 182.97 seconds actually executing testcases
WITH : Spent 104.227 seconds actually executing testcases
WITHOUT: WITH:
real 3m36.053s real 2m10.610s
user 0m42.323s user 0m41.939s
sys 0m2.844s sys 0m2.356s
```
Talks/Video
-----------
libeatmydata was the product of a talk I gave back at linux.conf.au 2007, titled
"Eat My Data: How Everybody gets File IO Wrong" - I also gave this talk at OSCON.
This talk went over the common mistakes people make when using POSIX file IO
routines.
You can watch a video recording of this talk at:
- https://youtu.be/LMe7hf2G1po
- http://www.linux.org.au/conf/2007/talk/278.html
Copyright
---------
(C)2007-2016 Stewart Smith
and other contributors (see AUTHORS)
See LICENSE for full text of GPLv3