Poor Write Speeds with RAID5 on 10.10

[not_the_messiah]

Hi,

I am getting extremely poor write speeds with my RAID. My setup is as follows:
> HP Proliant Microserver
> 4 2TB Samsung F4 drives
> 60GB root drive
> Ubuntu 10.10 64bit
> mdadm 3.2.2

I have two of the above servers, connected via gigabit LAN. The read speeds I am happy with, but write speeds are running at about 20Mb/s at the very best, which I don't think is that great. Especially when people with a similar setup on a machine like this are running at about 90MB/s write speeds...

My array is as follows (mdadm --detail -D /dev/md0):

/dev/md0:
Version : 1.2
Creation Time : Mon Jul 18 22:36:01 2011
Raid Level : raid5
Array Size : 5860531200 (5589.04 GiB 6001.18 GB)
Used Dev Size : 1953510400 (1863.01 GiB 2000.39 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent

Update Time : Tue Jul 19 15:30:29 2011
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0

Layout : left-symmetric
Chunk Size : 512K

Name : tim-ProLiant-MicroServer:0 (local to host tim-ProLiant-MicroServer)
UUID : 95e90209:102debea:33a66f2c:b903e0af
Events : 19

Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 8 33 1 active sync /dev/sdc1
2 8 49 2 active sync /dev/sdd1
3 8 65 3 active sync /dev/sde1

I have also started the partitions at 64 instead of 63 in a bid to correctly align the partitions, although this doesn't seem to have made any difference.

Can anyone offer any advice as I have been at this for days now, tearing down, rebuild etc, to no avail

Thanks in advance.

Tim

[gofasterplease]

you've got me worried. I've got an HP Proliant Microserver with 4 GB of RAM, and 4 samsung 2 TB f4 hard drives. I haven't yet made the RAID 5 with mdadm because I don't know what settings to use. I'm running fedora 14 if that makes a diff.