Edgar Fuß <[email protected]> wrote: > How often do these log flushes occur?
On a 6.1 kernel with RAIDOUTSTANDING=800 and -o log. Stress test raises load to around 10. > During the stess phase, what does > iostat -D -x -w 1 > show for the raid and for the components, especially in the time column? Here is an excerpt: device read KB/t r/s time MB/s write KB/t w/s time MB/s wd0 0.00 0 0.00 0.00 13.74 27 0.00 0.36 wd1 0.00 0 0.00 0.00 13.74 27 0.00 0.36 raid1 0.00 0 0.00 0.00 20.61 18 0.00 0.36 device read KB/t r/s time MB/s write KB/t w/s time MB/s wd0 0.00 0 0.06 0.00 12.70 306 0.06 3.80 wd1 0.00 0 0.14 0.00 12.70 306 0.14 3.80 raid1 0.00 0 0.14 0.00 18.51 210 0.14 3.80 device read KB/t r/s time MB/s write KB/t w/s time MB/s wd0 0.00 0 0.04 0.00 13.53 285 0.04 3.77 wd1 0.00 0 0.04 0.00 13.53 285 0.04 3.77 raid1 0.00 0 0.05 0.00 20.18 191 0.05 3.77 device read KB/t r/s time MB/s write KB/t w/s time MB/s wd0 0.00 0 0.04 0.00 13.34 304 0.04 3.96 wd1 16.00 1 0.04 0.02 13.34 304 0.04 3.96 raid1 16.00 1 0.05 0.02 20.28 200 0.05 3.96 device read KB/t r/s time MB/s write KB/t w/s time MB/s wd0 0.00 0 0.06 0.00 12.97 242 0.06 3.06 wd1 0.00 0 0.13 0.00 12.97 242 0.13 3.06 raid1 0.00 0 0.13 0.00 19.42 161 0.13 3.06 > During the stress, do you see small synchronous writes in NFS traffic? Output of your first script: 2908 getattr 1140 lookup 969 access 273 fsstat 195 write 145 commit 110 create 102 setattr 94 remove 23 read Output of your second script: 167 549 unstable 28 549 filesync And here is the iostat without -o log (load barely raise to 1) device read KB/t r/s time MB/s write KB/t w/s time MB/s wd0 0.00 0 0.00 0.00 14.86 48 0.00 0.69 wd1 0.00 0 0.00 0.00 14.86 48 0.00 0.69 raid1 0.00 0 0.00 0.00 22.30 32 0.00 0.69 device read KB/t r/s time MB/s write KB/t w/s time MB/s wd0 0.00 0 0.07 0.00 7.75 227 0.07 1.72 wd1 0.00 0 0.06 0.00 7.75 227 0.06 1.72 raid1 0.00 0 0.09 0.00 7.85 224 0.09 1.72 device read KB/t r/s time MB/s write KB/t w/s time MB/s wd0 0.00 0 0.01 0.00 14.08 50 0.01 0.69 wd1 2.00 1 0.01 0.00 14.08 50 0.01 0.69 raid1 2.00 1 0.02 0.00 32.64 22 0.02 0.69 device read KB/t r/s time MB/s write KB/t w/s time MB/s wd0 0.00 0 0.00 0.00 10.40 20 0.00 0.20 wd1 16.00 1 0.05 0.02 10.40 20 0.05 0.20 raid1 16.00 1 0.05 0.02 14.86 14 0.05 0.20 -- Emmanuel Dreyfus http://hcpnet.free.fr/pubz [email protected]
