Harddrive vs ramdisk vs tmpfs benchmark

tl;dr: tmpfs and ramdisk are super faster than physical hard disk. Tmpfs and ramdisk are about the same speed.

Based on the discussion in this thread I decided to attempt to simulate world read/write performance on the three mediums. It is reported that ramdisks are more efficient than tmpfs. However unlike a ramdisk, tmpfs size dynamically, so will only take up the ram it needs. I'll update this post as I go along.

I should note that I've never done any benchmarking before, so if my methology can be improved, please let me know

The program used is called iozone. It provides a number of benchmarks for disk io performance. I am using 10 read/write threads to work with 100 4k files. I created a minetest directory to which filesystems are mounted to. I will report random read, random write and random mix use(50/50).

Script used:

Code:

iozone -r 4k -s 4k -t 10 -F minetest/tmp0 minetest/tmp1 minetest/tmp2 minetest/tmp3 minetest/tmp4 minetest/tmp5 minetest/tmp6 minetest/tmp7 minetest/tmp8 minetest/tmp9 minetest/tmp10 minetest/tmp0 minetest/tmp11 minetest/tmp12 minetest/tmp13 minetest/tmp14 minetest/tmp15 minetest/tmp16 minetest/tmp17 minetest/tmp18 minetest/tmp19 minetest/tmp20 minetest/tmp21 minetest/tmp22 minetest/tmp23 minetest/tmp24 minetest/tmp25 minetest/tmp26 minetest/tmp27 minetest/tmp28 minetest/tmp29 minetest/tmp30 minetest/tmp31 minetest/tmp32 minetest/tmp33 minetest/tmp34 minetest/tmp35 minetest/tmp36 minetest/tmp37 minetest/tmp38 minetest/tmp39 minetest/tmp40 minetest/tmp41 minetest/tmp42 minetest/tmp43 minetest/tmp44 minetest/tmp45 minetest/tmp46 minetest/tmp47 minetest/tmp48 minetest/tmp49 minetest/tmp50 minetest/tmp51 minetest/tmp52 minetest/tmp53 minetest/tmp54 minetest/tmp55 minetest/tmp56 minetest/tmp57 minetest/tmp58 minetest/tmp59 minetest/tmp60 minetest/tmp61 minetest/tmp62 minetest/tmp63 minetest/tmp64 minetest/tmp65 minetest/tmp66 minetest/tmp67 minetest/tmp68 minetest/tmp69 minetest/tmp70 minetest/tmp71 minetest/tmp72 minetest/tmp73 minetest/tmp74 minetest/tmp75 minetest/tmp76 minetest/tmp77 minetest/tmp78 minetest/tmp79 minetest/tmp80 minetest/tmp81 minetest/tmp82 minetest/tmp83 minetest/tmp84 minetest/tmp85 minetest/tmp86 minetest/tmp87 minetest/tmp88 minetest/tmp89 minetest/tmp90 minetest/tmp91 minetest/tmp92 minetest/tmp93 minetest/tmp94 minetest/tmp95 minetest/tmp96 minetest/tmp97 minetest/tmp98 minetest/tmp99

System 1: Desktop -- Kubuntu Natty 64 bit.
350 MB HD, 7200 rmp with ext4 partition.
Core2 Duo 6700@ 2.66 GHz
4 MB RAM
This is a standard desktop, this simulation represents users who run a server on their home machine. Important values bolded.

HDD:
Children see throughput for 10 random readers = 142414.30 KB/sec
Parent sees throughput for 10 random readers = 225.30 KB/sec
Min throughput per process = 0.00 KB/sec
Max throughput per process = 142414.30 KB/sec
Avg throughput per process = 14241.43 KB/sec
Min xfer = 0.00 KB

Children see throughput for 10 mixed workload = 114281.78 KB/sec
Parent sees throughput for 10 mixed workload = 48.99 KB/sec
Min throughput per process = 0.00 KB/sec
Max throughput per process = 114281.78 KB/sec
Avg throughput per process = 11428.18 KB/sec
Min xfer = 0.00 KB

Children see throughput for 10 random writers = 129248.69 KB/sec
Parent sees throughput for 10 random writers = 49.23 KB/sec
Min throughput per process = 0.00 KB/sec
Max throughput per process = 129248.69 KB/sec
Avg throughput per process = 12924.87 KB/sec
Min xfer = 0.00 KB

TMPFS -- default values (sudo mount -t tmpfs tmpfs minetest).
Children see throughput for 10 random readers = 144133.31 KB/sec
Parent sees throughput for 10 random readers = 2357.71 KB/sec
Min throughput per process = 0.00 KB/sec
Max throughput per process = 142414.30 KB/sec
Avg throughput per process = 14413.33 KB/sec
Min xfer = 0.00 KB

Children see throughput for 10 mixed workload = 147419.83 KB/sec
Parent sees throughput for 10 mixed workload = 1097.71 KB/sec
Min throughput per process = 0.00 KB/sec
Max throughput per process = 147419.83 KB/sec
Avg throughput per process = 14741.98 KB/sec

Children see throughput for 10 random writers = 147419.83 KB/sec
Parent sees throughput for 10 random writers = 953.48 KB/sec
Min throughput per process = 0.00 KB/sec
Max throughput per process = 147419.83 KB/sec
Avg throughput per process = 14741.98 KB/sec

RAMDISK -- 256MB (sudo mount -t ramfs -o mode=1777,size=256m ramfs minetest/)
Children see throughput for 10 random readers = 120868.35 KB/sec
Parent sees throughput for 10 random readers = 1003.25 KB/sec
Min throughput per process = 0.00 KB/sec
Max throughput per process = 120868.35 KB/sec
Avg throughput per process = 12086.84 KB/sec

Children see throughput for 10 mixed workload = 200191.84 KB/sec
Parent sees throughput for 10 mixed workload = 1108.67 KB/sec
Min throughput per process = 0.00 KB/sec
Max throughput per process = 200191.84 KB/sec
Avg throughput per process = 20019.18 KB/sec

Children see throughput for 10 random writers = 267128.91 KB/sec
Parent sees throughput for 10 random writers = 746.29 KB/sec
Min throughput per process = 0.00 KB/sec
Max throughput per process = 267128.91 KB/sec
Avg throughput per process = 26712.89 KB/sec

Summery -- mixed workload -- First run:
Disk: 48.99 KB/sec
TMPFS: 1097.71 KB/sec
RAMDISK: 1108.67 KB/sec

10 run average:
Tmpfs: 879.6
RAMDISK: 942.4
Two tailed t score: 0.49
Therefor the differences in speed are NOT significant, which means for this test run the differences between tmpfs and ramdisk are not significant.

 

Thanks for settling that debate.