And the Winner Is!

Stripe size of 128K and Allocation Unit Size of 32K.

Raid Performance Results

Performance results being compiled...

RAID5 Performance Issues

I'm running out of disk space on my home media server and therefore decided to upgrade to a RAID5 configuration with 4x1.5TB drives. The drives are Seagate ST31500341AS and I'm housing them in an 8-bay ESATA case Rosewill RSV-S8 (SII-3132 chipset).

The problem is that I'm seeing low write speeds in Vista. It is software based RAID however CPU utilization is low so I believe there's room for improvement. I'll be tweaking the raid chunk size (stripe size) and NTFS allocation unit size this weekend to see where the sweet spot is for read/writes of large media files.

I just wrote the following powershell script to test the read and write speeds. All I need to do is change the file_name, test_folder and control_folder variables and I'm set.

#$erroractionpreference = "SilentlyContinue"
$file_name = "test.avi"
$test_folder = "L:\"
$control_folder = "K:\"
$num_attempts = 3
$total_write_time = 0
$total_read_time = 0

#writes
for($i = 0; $i -lt $num_attempts; $i++)
{
$source = "$control_folder$file_name"
$destination = "$test_folder"

$remove = "$destination$file_name"
remove-item $remove

$total_write_time += $(measure-command{xcopy.exe $source $destination /y}).totalmilliseconds
echo $("write test " + ($i+1).tostring() + " complete.")
}

#reads
for($i = 0; $i -lt $num_attempts; $i++)
{
$source = "$test_folder$file_name"
$destination = "$control_folder"

$remove = "$destination$file_name"
remove-item $remove

$total_read_time += $(measure-command{xcopy.exe $source $destination /y}).totalmilliseconds
echo $("read test " + ($i+1).tostring() + " complete.")
}

$average = $($total_write_time / $num_attempts / 1000)
echo "Average write time: $average seconds"

$average = $($total_read_time / $num_attempts / 1000)
echo "Average read time: $average seconds"