Yet another cool use for SSDs
I did a test for a SSD as a external journal for a ext3 based single SCSI drive with some mildly interesting results ! I was going to rerun with a larger test size but ran out of time. If anyone re-runs this test and can send me the results I would like to see them.
(remove old journal)
tune2fs -O ^has_journal /dev/sdc1
(add new journal a 400M parition on a SSD)
mke2fs -b 4096 -O journal_dev -J device=/dev/sdk1,size=400 /dev/sdk1
tune2fs -j -J device=/dev/sdk1,size=400 /dev/sdc1
All tests done on a Dual Xeon 2.8Ghz (HT enabled) 800FSB 1M cache
Benchmarks used :
tiobench (from RPMForge) run from CLI with defaults `tiobench`
dd : ` dd if=/dev/zero of=/mnt/test.tmp bs=256k count=10000`
Results
400 MB SSD journal
DD: (2.6 GB) copied, 51.3763 seconds, 51.0 MB/s
DD: (2.6 GB) copied, 51.3763 seconds, 51.0 MB/s
Sequential Reads
2.6.18-194.el5 2000 4096 1 ###### 99.94% 0.003 0.13 0.00000 0.00000 1211
2.6.18-194.el5 2000 4096 2 ###### 399.0% 0.004 0.25 0.00000 0.00000 518
2.6.18-194.el5 2000 4096 4 ###### 1545.% 0.006 34.99 0.00000 0.00000 151
2.6.18-194.el5 2000 4096 8 ###### 3038.% 0.012 140.04 0.00000 0.00000 77
Random Reads
2.6.18-194.el5 2000 4096 1 836.90 96.41% 0.004 0.03 0.00000 0.00000 868
2.6.18-194.el5 2000 4096 2 ###### 370.3% 0.004 0.03 0.00000 0.00000 434
2.6.18-194.el5 2000 4096 4 ###### 1405.% 0.006 0.41 0.00000 0.00000 140
2.6.18-194.el5 2000 4096 8 ###### 779.5% 0.006 0.05 0.00000 0.00000 208
Sequential Writes
2.6.18-194.el5 2000 4096 1 43.03 23.59% 0.083 2692.94 0.00039 0.00000 182
2.6.18-194.el5 2000 4096 2 41.65 64.84% 0.170 2302.42 0.00078 0.00000 64
2.6.18-194.el5 2000 4096 4 41.87 219.0% 0.322 2970.18 0.00176 0.00000 19
2.6.18-194.el5 2000 4096 8 40.39 422.4% 0.667 3098.38 0.01211 0.00000 10
Random Writes
2.6.18-194.el5 2000 4096 1 14.72 5.746% 0.008 0.03 0.00000 0.00000 256
2.6.18-194.el5 2000 4096 2 14.63 16.48% 0.011 0.05 0.00000 0.00000 89
2.6.18-194.el5 2000 4096 4 56.14 103.4% 0.019 16.04 0.00000 0.00000 54
2.6.18-194.el5 2000 4096 8 40.74 161.6% 0.023 11.21 0.00000 0.00000 25
Default Journal on same disk
DD: (2.6 GB) copied, 100.868 seconds, 26.0 MB/s
Sequential Reads
2.6.18-194.el5 2000 4096 1 ###### 99.85% 0.003 1.80 0.00000 0.00000 1184
2.6.18-194.el5 2000 4096 2 ###### 397.9% 0.004 1.64 0.00000 0.00000 522
2.6.18-194.el5 2000 4096 4 ###### 1590.% 0.006 0.22 0.00000 0.00000 147
2.6.18-194.el5 2000 4096 8 ###### 2807.% 0.011 430.45 0.00000 0.00000 84
Random Reads
2.6.18-194.el5 2000 4096 1 840.96 96.87% 0.004 0.02 0.00000 0.00000 868
2.6.18-194.el5 2000 4096 2 ###### 370.3% 0.004 0.03 0.00000 0.00000 434
2.6.18-194.el5 2000 4096 4 ###### 1382.% 0.006 0.69 0.00000 0.00000 138
2.6.18-194.el5 2000 4096 8 ###### 1339.% 0.007 4.06 0.00000 0.00000 145
Sequential Writes
2.6.18-194.el5 2000 4096 1 23.28 13.37% 0.164 1449.18 0.00000 0.00000 174
2.6.18-194.el5 2000 4096 2 23.16 37.65% 0.330 1522.12 0.00000 0.00000 61
2.6.18-194.el5 2000 4096 4 21.45 125.1% 0.706 1493.51 0.00000 0.00000 17
2.6.18-194.el5 2000 4096 8 21.07 236.6% 1.419 1943.53 0.00000 0.00000 9
Random Writes
2.6.18-194.el5 2000 4096 1 15.15 4.749% 0.008 0.03 0.00000 0.00000 319
2.6.18-194.el5 2000 4096 2 15.22 14.60% 0.011 0.06 0.00000 0.00000 104
2.6.18-194.el5 2000 4096 4 44.56 101.8% 0.020 0.08 0.00000 0.00000 44
2.6.18-194.el5 2000 4096 8 21.06 73.30% 0.018 0.28 0.00000 0.00000 29