[Drbd-dev] [PATCH v4 01/11] block: make generic_make_request handle arbitrarily sized bios

[Ming Lin]

On Thu, 2015-06-04 at 17:06 -0400, Mike Snitzer wrote:
> We need to test on large HW raid setups like a Netapp filer (or even
> local SAS drives connected via some SAS controller).  Like a 8+2 drive
> RAID6 or 8+1 RAID5 setup.  Testing with MD raid on JBOD setups with 8
> devices is also useful.  It is larger RAID setups that will be more
> sensitive to IO sizes being properly aligned on RAID stripe and/or chunk
> size boundaries.

Here are tests results of xfs/ext4/btrfs read/write on HW RAID6/MD RAID6/DM stripe target.
Each case run 0.5 hour, so it took 36 hours to finish all the tests on 4.1-rc4 and 4.1-rc4-patched kernels.

No performance regressions were introduced.

Test server: Dell R730xd(2 sockets/48 logical cpus/264G memory)
HW RAID6/MD RAID6/DM stripe target were configured with 10 HDDs, each 280G
Stripe size 64k and 128k were tested.

devs="/dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg /dev/sdh /dev/sdi /dev/sdj /dev/sdk"
spare_devs="/dev/sdl /dev/sdm"
stripe_size=64 (or 128)

MD RAID6 was created by:
mdadm --create --verbose /dev/md0 --level=6 --raid-devices=10 $devs --spare-devices=2 $spare_devs -c $stripe_size

DM stripe target was created by:
pvcreate $devs
vgcreate striped_vol_group $devs
lvcreate -i10 -I${stripe_size} -L2T -nstriped_logical_volume striped_vol_group

Here is an example of fio script for stripe size 128k:
[global]
ioengine=libaio
iodepth=64
direct=1
runtime=1800
time_based
group_reporting
numjobs=48
gtod_reduce=0
norandommap
write_iops_log=fs

[job1]
bs=1280K
directory=/mnt
size=5G
rw=read

All results here: http://minggr.net/pub/20150608/fio_results/

Results summary:

1. HW RAID6: stripe size 64k
		4.1-rc4		4.1-rc4-patched
		-------		---------------
		(MB/s)		(MB/s)
xfs read:	821.23		812.20  -1.09%
xfs write:	753.16		754.42  +0.16%
ext4 read:	827.80		834.82  +0.84%
ext4 write:	783.08		777.58  -0.70%
btrfs read:	859.26		871.68  +1.44%
btrfs write:	815.63		844.40  +3.52%

2. HW RAID6: stripe size 128k
		4.1-rc4		4.1-rc4-patched
		-------		---------------
		(MB/s)		(MB/s)
xfs read:	948.27		979.11  +3.25%
xfs write:	820.78		819.94  -0.10%
ext4 read:	978.35		997.92  +2.00%
ext4 write:	853.51		847.97  -0.64%
btrfs read:	1013.1		1015.6  +0.24%
btrfs write:	854.43		850.42  -0.46%

3. MD RAID6: stripe size 64k
		4.1-rc4		4.1-rc4-patched
		-------		---------------
		(MB/s)		(MB/s)
xfs read:	847.34		869.43  +2.60%
xfs write:	198.67		199.03  +0.18%
ext4 read:	763.89		767.79  +0.51%
ext4 write:	281.44		282.83  +0.49%
btrfs read:	756.02		743.69  -1.63%
btrfs write:	268.37		265.93  -0.90%

4. MD RAID6: stripe size 128k
		4.1-rc4		4.1-rc4-patched
		-------		---------------
		(MB/s)		(MB/s)
xfs read:	993.04		1014.1  +2.12%
xfs write:	293.06		298.95  +2.00%
ext4 read:	1019.6		1020.9  +0.12%
ext4 write:	371.51		371.47  -0.01%
btrfs read:	1000.4		1020.8  +2.03%
btrfs write:	241.08		246.77  +2.36%

5. DM: stripe size 64k
		4.1-rc4		4.1-rc4-patched
		-------		---------------
		(MB/s)		(MB/s)
xfs read:	1084.4		1080.1  -0.39%
xfs write:	1071.1		1063.4  -0.71%
ext4 read:	991.54		1003.7  +1.22%
ext4 write:	1069.7		1052.2  -1.63%
btrfs read:	1076.1		1082.1  +0.55%
btrfs write:	968.98		965.07  -0.40%

6. DM: stripe size 128k
		4.1-rc4		4.1-rc4-patched
		-------		---------------
		(MB/s)		(MB/s)
xfs read:	1020.4		1066.1  +4.47%
xfs write:	1058.2		1066.6  +0.79%
ext4 read:	990.72		988.19  -0.25%
ext4 write:	1050.4		1070.2  +1.88%
btrfs read:	1080.9		1074.7  -0.57%
btrfs write:	975.10		972.76  -0.23%