Phase 3: Tuning the readahead buffer

Figures sorted by stripe size

All tests ran on a 1.8 TB xfs partition.
Filesystem was formatted with -d su=stripesize,sw=8 options (we have 8 disks)

stripe=64k

bonnie -u nobody -d . -s 1024 -n 16 -r 64

bonnie -u nobody -d . -s 1024 -n 16

time sh -c "dd if=/dev/zero bs=64k count=16384 of=jonagy ; sync"
time dd of=/dev/null bs=64k count=16384 if=jonagy

time sh -c "dd if=/dev/zero bs=1024k count=65536 of=jonagy2 ; sync"
time dd of=/dev/null bs=1024k count=65536 if=jonagy2

cstream -B 1m -b 1m -n 1024m -i - -o cgigasz -v 2
cstream -B 1m -b 1m -n 1024m -o - -i cgigasz -v 2

cstream -B 1m -b 1m -n 65536m -i - -o cgigasz2 -v 2
cstream -B 1m -b 1m -n 65536m -o - -i cgigasz2 -v 2

stripe=128k

bonnie -u nobody -d . -s 1024 -n 16 -r 64

bonnie -u nobody -d . -s 1024 -n 16

time sh -c "dd if=/dev/zero bs=64k count=16384 of=jonagy ; sync"
time dd of=/dev/null bs=64k count=16384 if=jonagy

time sh -c "dd if=/dev/zero bs=1024k count=65536 of=jonagy2 ; sync"
time dd of=/dev/null bs=1024k count=65536 if=jonagy2

cstream -B 1m -b 1m -n 1024m -i - -o cgigasz -v 2
cstream -B 1m -b 1m -n 1024m -o - -i cgigasz -v 2

cstream -B 1m -b 1m -n 65536m -i - -o cgigasz2 -v 2
cstream -B 1m -b 1m -n 65536m -o - -i cgigasz2 -v 2

stripe=256k

bonnie -u nobody -d . -s 1024 -n 16 -r 64

bonnie -u nobody -d . -s 1024 -n 16

time sh -c "dd if=/dev/zero bs=64k count=16384 of=jonagy ; sync"
time dd of=/dev/null bs=64k count=16384 if=jonagy

time sh -c "dd if=/dev/zero bs=1024k count=65536 of=jonagy2 ; sync"
time dd of=/dev/null bs=1024k count=65536 if=jonagy2

cstream -B 1m -b 1m -n 1024m -i - -o cgigasz -v 2
cstream -B 1m -b 1m -n 1024m -o - -i cgigasz -v 2

cstream -B 1m -b 1m -n 65536m -i - -o cgigasz2 -v 2
cstream -B 1m -b 1m -n 65536m -o - -i cgigasz2 -v 2

stripe=512k

bonnie -u nobody -d . -s 1024 -n 16 -r 64

bonnie -u nobody -d . -s 1024 -n 16

time sh -c "dd if=/dev/zero bs=64k count=16384 of=jonagy ; sync"
time dd of=/dev/null bs=64k count=16384 if=jonagy

time sh -c "dd if=/dev/zero bs=1024k count=65536 of=jonagy2 ; sync"
time dd of=/dev/null bs=1024k count=65536 if=jonagy2

cstream -B 1m -b 1m -n 1024m -i - -o cgigasz -v 2
cstream -B 1m -b 1m -n 1024m -o - -i cgigasz -v 2

cstream -B 1m -b 1m -n 65536m -i - -o cgigasz2 -v 2
cstream -B 1m -b 1m -n 65536m -o - -i cgigasz2 -v 2

stripe=1M

>
bonnie -u nobody -d . -s 1024 -n 16 -r 64

bonnie -u nobody -d . -s 1024 -n 16

time sh -c "dd if=/dev/zero bs=1M count=16384 of=jonagy ; sync"
time dd of=/dev/null bs=1M count=16384 if=jonagy

time sh -c "dd if=/dev/zero bs=1024k count=65536 of=jonagy2 ; sync"
time dd of=/dev/null bs=1024k count=65536 if=jonagy2

cstream -B 1m -b 1m -n 1024m -i - -o cgigasz -v 2
cstream -B 1m -b 1m -n 1024m -o - -i cgigasz -v 2

cstream -B 1m -b 1m -n 65536m -i - -o cgigasz2 -v 2
cstream -B 1m -b 1m -n 65536m -o - -i cgigasz2 -v 2

The same figures ordered by test program