Re: [Qemu-devel] Re: [RFC] Disk integrity in QEMU

[Laurent Vivier]

Hi,

I've made a benchmark using a database:
mysql and sysbench in OLTP mode.

cache=off seems to be the best choice in this case...

mysql database
http://sysbench.sourceforge.net

sysbench --test=oltp

200,000 requests on 2,000,000 rows table.

                 | total time | per-request stat (ms) |
                 |  (seconds) |  min  |  avg  |  max  |
-----------------+------------+-------+-------+-------+
baremetal        |   208.6237 |   2.5 |  16.7 | 942.6 |
-----------------+------------+-------+-------+-------+
cache=on         |   642.2962 |   2.5 |  51.4 | 326.9 |
-----------------+------------+-------+-------+-------+
cache=on,O_DSYNC |   646.6570 |   2.7 |  51.7 | 347.0 |
-----------------+------------+-------+-------+-------+
cache=off        |   635.4424 |   2.9 |  50.8 | 399.5 |
-----------------+------------+-------+-------+-------+

Laurent
-- 
------------------ address@hidden  ------------------
"Tout ce qui est impossible reste à accomplir"    Jules Verne
"Things are only impossible until they're not" Jean-Luc Picard