poor write performances with RAID 5 Raidframe

["Emile `iMil' Heitor" <imil%home.imil.net@localhost>]

Hi,

I'm witnessing poor performances while writing to a RAID 5 Raidframe I setup
to be my home NAS a couple of months ago.
Following some documentations, tutorials, and mailing-list posts, I think I
had everything aligned right as the following configuration suggests:

raid1.conf:
START array
# numRow numCol numSpare
1 3 0

START disks
/dev/wd2a
/dev/wd3a
/dev/wd4a

START layout
# sectPerSU SUsPerParityUnit SUsPerReconUnit RAID_level_5
64 1 1 5

START queue
fifo 100

# gpt show raid1
       start        size  index  contents
           0           1         PMBR
           1           1         Pri GPT header
           2          32         Pri GPT table
          34          94
         128  7814057951      1  GPT part - NetBSD FFSv1/FFSv2
  7814058079          32         Sec GPT table
  7814058111           1         Sec GPT header

# dkctl raid1 listwedges
/dev/rraid1d: 1 wedge:
dk0: 5bdb599c-744a-11e3-9160-002354666e0f, 7814057951 blocks at 128, type: ffs

newfs(8) was done like this:

# newfs -O2 -b64k -I dk0

The disks involved are Seagate Barracuda which are known to have as such high
write transfer rate as ~100MB/s, and I merely get a 25MB/s with those:

$ dd if=/dev/zero of=/export/imil/tmp/test bs=1m count=1000
1000+0 records in
1000+0 records out
1048576000 bytes transferred in 42.619 secs (24603486 bytes/sec)

On the other hand, read speed is really good:

$ dd if=/export/imil/media/foobar_adventures.mp4 of=/dev/null bs=1m
1395+1 records in
1395+1 records out
1463376863 bytes transferred in 7.899 secs (185261028 bytes/sec)

Any advice on this matter? Does this configuration looks good?

Thanks,

----------------------------------------------------------------
Emile `iMil' Heitor * <imil@{home.imil.net,NetBSD.org,gcu.info}>
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