Jeff,
#!/bin/bash
#Random throughput
echo "Random throughput"
sync
fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4M --iodepth=256 --size=10G --readwrite=randread --ramp_time=4
#Random IOPS
echo "Random IOPS"
sync
fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=256 --size=4G --readwrite=randread --ramp_time=4
#Sequential throughput
echo "Sequential throughput"
sync
fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4M --iodepth=256 --size=10G --readwrite=read --ramp_time=4
#Sequential IOPS
echo "Sequential IOPS"
sync
fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=256 --size=4G --readwrite=read --ramp_time=4
Performing the test you suggested, I get 128.5MB/s. Monitoring the test, I find that the throughput is constant from start to finish and that the iowait is also constant at 5%:
charles@hpdl380g6:~$ sudo sh -c 'time cat /mnt/data/postgresql/base/16385/* | wc -c'
[sudo] password for charles:
1.62user 179.94system 29:50.79elapsed 10%CPU (0avgtext+0avgdata 1920maxresident)k
448026264inputs+0outputs (0major+117minor)pagefaults 0swaps
241297594904
After making the changes to HugePage suggested by Rick Otten (above), I found slightly better results (135.7MB/s):
charles@hpdl380g6:~$ sudo sh -c 'time cat /mnt/data/postgresql/base/16385/* | wc -c'
[sudo] password for charles:
0.86user 130.84system 28:15.78elapsed 7%CPU (0avgtext+0avgdata 1820maxresident)k
471286792inputs+0outputs (1major+118minor)pagefaults 0swaps
241297594904
Could you suggest another way to benchmark random reads?
Thanks for your help!
Charles
