Measuring open/close IO performance

Local/NFS performance measured 2009-02-06

[cycles/s]	h1	h2	h4	remarks
s01	108	3.5	101	via NFS, zpool setup with 3 large vdevs
s13	109	4.1	115	via NFS, zpool setup with 8 small vdevs
d02	832	4.5	631	via NFS, Areca 16 disk RAID6
local	59282	3586	60301	h1,h2: Areca 4 disk RAID6, h4: Areca 8 disk RAID6
KERNEL	2.6.24.4	2.6.27.7	2.6.27.7	kernel at the time of testing

Measurements are done with this stupid little program

One word of caution concerning h2: This machine was always under a high load of 20+ (sometimes briefly up to 100) while tests were run. Big question is why.

local IO performance on h4

On the local h4 RAID6 with 8 disks the open/close program was run several times along with stress with either the --cpu x or the --vm x options. As soon as the number x comes close to the number of system cores the performance drops down significantly:

-- CarstenAulbert - 06 Feb 2009