环境介绍：

oracle10.2.0.4

REDHAT5.1 64BIT

MEM:16G

STOR:720G

RAID:5

今天要装一台备用数据库，操作系统都是安装好的，在安装完之后检测各项参数的时候发现重大问题，就是操作系统的I/0异常的慢：

RAID10：

[root@localhost u02]# dd if=/dev/zero of=testio bs=8192

392219+0 records in
392219+0 records out
3213058048 bytes (3.2 GB) copied, 13.2956 seconds, 242 MB/s

Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 29588.12 13.86 1460.40 0.06 132.43 184.04 101.84 73.98 0.59 87.13

avg-cpu: %user %nice %system %iowait %steal %idle
1.09 0.00 5.20 1.44 0.00 92.28

Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 79.00 45.00 120.00 0.18 0.77 11.68 1.14 6.74 5.09 84.00

avg-cpu: %user %nice %system %iowait %steal %idle
0.08 0.00 7.62 14.92 0.08 77.30

Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 32773.74 17.17 1345.45 0.07 119.44 179.62 98.07 67.45 0.70 95.35

avg-cpu: %user %nice %system %iowait %steal %idle
0.44 0.00 4.26 14.88 0.00 80.42

Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 43888.35 6.80 1965.05 0.03 179.87 186.84 141.22 71.18 0.49 97.48

avg-cpu: %user %nice %system %iowait %steal %idle
0.50 0.00 6.62 26.07 0.00 66.81

Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 44754.00 6.00 1964.00 0.02 181.86 189.09 146.11 73.80 0.51 100.40

avg-cpu: %user %nice %system %iowait %steal %idle
0.24 0.00 4.40 17.76 0.05 77.55

Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 46545.92 8.16 2040.82 0.03 189.54 189.48 149.80 73.16 0.50 102.45

[root@localhost u02]# time rm testio rm: remove regular file `testio'? y

real 0m2.235s
user 0m0.000s
sys 0m1.152s

RAID5:

[root@szpa-bak-db2 u02]# dd if=/dev/zero of=testio bs=8192440817+0 records in
440817+0 records out
3611172864 bytes (3.6 GB) copied, 17.1523 seconds, 211 MB/s

evice: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 7049.50 0.99 292.08 0.00 26.71 186.68 143.37 476.16 3.38 99.01

avg-cpu: %user %nice %system %iowait %steal %idle
0.23 0.00 3.99 11.50 0.00 84.28

Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 5740.00 2.00 273.00 0.01 24.73 184.26 144.84 525.63 3.65 100.40

avg-cpu: %user %nice %system %iowait %steal %idle
0.00 0.00 3.15 7.51 0.00 89.33

Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 6352.48 0.99 280.20 0.00 25.47 185.55 143.19 517.85 3.54 99.41

avg-cpu: %user %nice %system %iowait %steal %idle
0.00 0.00 0.60 12.81 0.00 86.59

Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 5703.00 1.00 245.00 0.00 22.35 186.08 143.17 562.78 4.08 100.40

[root@szpa-bak-db2 u02]# time rm testio rm: remove regular file `testio'? y

real 1m6.138s
user 0m0.000s
sys 0m0.904s