Tests are done across four 7200RPM SATAII drives on a PCI-X card sitting on a PCI (32-bit, 133MB/sec theoretical max) bus, probably the slowest bus configuration possible, and then again after being moved to a motherboard with dual PCI-X slots. Server is running Ubuntu 9.10 AMD64 Server.
Benchmark is a simple ‘dd’ sequential read and write.
write: dd if=/dev/zero of=/dev/md2 bs=1M
read: dd if=/dev/md2 of=/dev/null bs=1M
mdadm –create /dev/md2 –verbose –level=10 –layout=n2 –raid-devices=4 /dev/sd[ftlm]1
| PCI | PCI-X | |
| write: | 13.2 MB/s | 144 MB/s |
| read: | 4.0 MB/s | 89.3 MB/s |
mdadm –create /dev/md2 –verbose –level=10 –layout=f2 –raid-devices=4 /dev/sd[ftlm]1
| PCI | PCI-X | |
| write: | 48.3 MB/s | 131 MB/s |
| read: | 92.7 MB/s | 138 MB/s |
mdadm –create /dev/md2 –verbose –level=10 –layout=o2 –raid-devices=4 /dev/sd[ftlm]1
| PCI | PCI-X | |
| write: | 47.4 MB/s | 135 MB/s |
| read: | 98.7 MB/s | 142 MB/s |
And more comparisons:
RAID1 (PCI)
write: 38.9 MB/s
read: 64.8 MB/s
Single Disk (PCI)
write: 59.4 MB/s
read: 71.9 MB/s