I'm running Fedora Core 3 (2.6.12-1.1376_FC3) with a software RAID 1+0 setup. I am getting great read performance but extremely slow writes (I *think* slower than even the hit from the mirroring). Also strange that my raid has nearly the exact same performance as my sata (boot) drive.

The physical setup is 3 160GB HD, 1 200GB HD; 2x on mobo IDE controllers, 2x on SIIG PCI IDE Ultra ATA 133 controller (all drives are masters on their own channel). 2 drives are 133, 2 are 100. the raid config is a stripe across two mirrors.

other system specs are:
Athlon XP 3000+
512 MB DDR400
Abit KV7 mobo
Sony DVD burner on a second SIIG PCI IDE Ultra ATA 133 controller.

The quick summary of tiobench results for my RAID is
~380MB/s seq read
~350MB/s random read
~60MB/s seq write
~6MB/s random write

**tiobench results for RAID
[root@wagner bin]# tiotest -f 25 -d /home
Tiotest results for 4 concurrent io threads:
,----------------------------------------------------------------------.
| Item | Time | Rate | Usr CPU | Sys CPU |
+-----------------------+----------+--------------+----------+---------+
| Write 100 MBs | 1.7 s | 57.904 MB/s | 2.1 % | 207.5 % |
| Random Write 16 MBs | 2.7 s | 5.779 MB/s | 0.0 % | 13.2 % |
| Read 100 MBs | 0.3 s | 379.538 MB/s | 5.7 % | 249.7 % |
| Random Read 16 MBs | 0.0 s | 350.376 MB/s | 2.2 % | 165.9 % |
`----------------------------------------------------------------------'
Tiotest latency results:
,-------------------------------------------------------------------------.
| Item | Average latency | Maximum latency | % >2 sec | % >10 sec |
+--------------+-----------------+-----------------+----------+-----------+
| Write | 0.096 ms | 352.546 ms | 0.00000 | 0.00000 |
| Random Write | 0.013 ms | 0.055 ms | 0.00000 | 0.00000 |
| Read | 0.025 ms | 159.998 ms | 0.00000 | 0.00000 |
| Random Read | 0.017 ms | 33.753 ms | 0.00000 | 0.00000 |
|--------------+-----------------+-----------------+----------+-----------|
| Total | 0.054 ms | 352.546 ms | 0.00000 | 0.00000 |
`--------------+-----------------+-----------------+----------+-----------'

**tiobench results for boot drive (SATA 80GB):
[root@wagner bin]# tiotest -f 25 -d /tmp
Tiotest results for 4 concurrent io threads:
,----------------------------------------------------------------------.
| Item | Time | Rate | Usr CPU | Sys CPU |
+-----------------------+----------+--------------+----------+---------+
| Write 100 MBs | 3.3 s | 30.137 MB/s | 1.0 % | 67.2 % |
| Random Write 16 MBs | 3.6 s | 4.296 MB/s | 0.3 % | 7.8 % |
| Read 100 MBs | 0.3 s | 376.705 MB/s | 7.9 % | 261.4 % |
| Random Read 16 MBs | 0.0 s | 353.907 MB/s | 4.5 % | 169.8 % |
`----------------------------------------------------------------------'
Tiotest latency results:
,-------------------------------------------------------------------------.
| Item | Average latency | Maximum latency | % >2 sec | % >10 sec |
+--------------+-----------------+-----------------+----------+-----------+
| Write | 0.067 ms | 186.843 ms | 0.00000 | 0.00000 |
| Random Write | 0.014 ms | 0.134 ms | 0.00000 | 0.00000 |
| Read | 0.026 ms | 179.993 ms | 0.00000 | 0.00000 |
| Random Read | 0.017 ms | 33.124 ms | 0.00000 | 0.00000 |
|--------------+-----------------+-----------------+----------+-----------|
| Total | 0.043 ms | 186.843 ms | 0.00000 | 0.00000 |
`--------------+-----------------+-----------------+----------+-----------'


**/etc/mdadm.conf:

ARRAY /dev/md2 level=raid0 num-devices=2
devices=/dev/md0,/dev/md1
ARRAY /dev/md1 level=raid1 num-devices=2
devices=/dev/hdc1,/dev/hdk1
ARRAY /dev/md0 level=raid1 num-devices=2
devices=/dev/hda1,/dev/hdi1

**/proc/mdstat:

Personalities : [raid0] [raid1] [raid5]
md2 : active raid0 md1[1] md0[0]
317122752 blocks 64k chunks

md1 : active raid1 hdk1[1] hdc1[0]
156288256 blocks [2/2] [UU]

md0 : active raid1 hdi1[1] hda1[0]
160834624 blocks [2/2] [UU]

**Hard drive specs are:

/dev/hda:

Model=Maxtor 6B200R0, FwRev=BAH41G10, SerialNo=B5045ERH
Config={ Fixed }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=57
BuffType=DualPortCache, BuffSize=16384kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=268435455
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
AdvancedPM=yes: disabled (255) WriteCache=enabled
Drive conforms to: (null):

/dev/hdc:

Model=ST3160023A, FwRev=8.01, SerialNo=5JS6GYKR
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs RotSpdTol>.5% }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
BuffType=unknown, BuffSize=8192kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=268435455
IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
AdvancedPM=no WriteCache=enabled
Drive conforms to: ATA/ATAPI-6 T13 1410D revision 2:

/dev/hdi:

Model=HDT722516DLAT80, FwRev=V43OA70A, SerialNo=VD271BTCC9LPWC
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=51
BuffType=DualPortCache, BuffSize=7674kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=268435455
IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
AdvancedPM=yes: disabled (255) WriteCache=enabled
Drive conforms to: Reserved:

/dev/hdk:

Model=ST3160023A, FwRev=8.01, SerialNo=5JS641TW
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs RotSpdTol>.5% }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
BuffType=unknown, BuffSize=8192kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=268435455
IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
AdvancedPM=no WriteCache=enabled
Drive conforms to: ATA/ATAPI-6 T13 1410D revision 2:

**lspci output
00:00.0 Host bridge: VIA Technologies, Inc. VT8377 [KT400/KT600 AGP] Host Bridge (rev 80)
00:01.0 PCI bridge: VIA Technologies, Inc. VT8237 PCI Bridge
00:09.0 Unknown mass storage controller: Silicon Image, Inc. (formerly CMD Technology Inc) PCI0680 Ultra ATA-133 Host Controller (rev 02)
00:0a.0 Unknown mass storage controller: Silicon Image, Inc. (formerly CMD Technology Inc) PCI0680 Ultra ATA-133 Host Controller (rev 02)
00:0f.0 RAID bus controller: VIA Technologies, Inc. VIA VT6420 SATA RAID Controller (rev 80)
00:0f.1 IDE interface: VIA Technologies, Inc. VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)
00:10.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.3 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.4 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 86)
00:11.0 ISA bridge: VIA Technologies, Inc. VT8237 ISA bridge [KT600/K8T800 South]
00:11.5 Multimedia audio controller: VIA Technologies, Inc. VT8233/A/8235/8237 AC97 Audio Controller (rev 60)
00:12.0 Ethernet controller: VIA Technologies, Inc. VT6102 [Rhine-II] (rev 7
01:00.0 VGA compatible controller: nVidia Corporation NV18 [GeForce4 MX 4000 AGP 8x] (rev c1)

Thanks for any help -
Spencer