Measuring open/close IO performance

Local/NFS performance measured 2009-02-06

[cycles/s]	h1	h2	h4	remarks
local	59282	3586	60301	h1,h2: Areca 4 disk RAID6, h4: Areca 8 disk RAID6
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
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