Comment 0 for bug 1657281

Dragan S. (dragan-s) wrote :

When we were doing testing on i3, we noticed that it is taking significantly longer to perform operations when using software RAID than without, we believe this is resolved in an upstream commit: http://kernel.ubuntu.com/git/ubuntu/ubuntu-xenial.git/commit/?id=87c279e613f848c691111b29d49de8df3f4f56da

So stock 4.4.0-59-generic performs ok:
$ sudo dd if=/dev/zero of=/dev/RDSVG/RDSRAIDLV bs=8k count=1000000 && sync
sudo: unable to resolve host ip-10-0-85-167
1000000+0 records in
1000000+0 records out
8192000000 bytes (8.2 GB, 7.6 GiB) copied, 54.3711 s, 151 MB/s

and the patch you originally providing works a little bit better (as expected):
$ uname -a
Linux ip-10-0-85-167 4.4.0-57-generic #78hf000000v20170110b0h3199a6e718db-Ubuntu SMP Tue Jan 10 02:53: x86_64 x86_64 x86_64 GNU/Linux
ubuntu@ip-10-0-85-167:~$ sudo dd if=/dev/zero of=/dev/RDSVG/RDSRAIDLV bs=8k count=1000000 && sync
sudo: unable to resolve host ip-10-0-85-167
1000000+0 records in
1000000+0 records out
8192000000 bytes (8.2 GB, 7.6 GiB) copied, 31.4108 s, 261 MB/s