Infrastructure Software

Hi all,

we have a problem with a software RAID 5. Its read performance is acceptable (61 MB/s via UFS filesystem) while its write performance is very very bad. 3 MB/s through UFS filesystem is not acceptable for a machine with 6 1.35 GHz CPUs and 7 very fast (10K) fiberchannel disks.

Raid 1 write performance is okay (42 MB/s) as well as the performance of individual disks (read: 74 MB/s).

The RAID 5 includes 5 disks (140 GB each, 10K) and was built using the standard commands from the man page and online help.

The hardware: SunFire 890, 6 CPUs (1.35 GHz US IV), 24 GB Memory, 7 disks (140 GB, 10K each). The machine runs SunOS 5.10.

The question is: What are the options to speed up write performance of RAID 5?

A much cheaper Athlon 64 based Linux system with slower SATA disks is much faster in reading (180 MB/s) and writing (around 50 MB/s) on a similar software raid 5.

While searching the net I found some benchmarks that indicate that "normally" write and read on solaris software raid 5 should be nearly the same.

Are there any ideas what to do?

Greetinga and thanks in advance,

Jan