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Hej

Jeg har været ved at måle harddisk I/O performance med hhv. hdparm og
bonnie++.
Det gav følgende resultater som jeg blev lidt forundret over:

hdparm -tT /dev/hda og /dev/hde og /dev/hdg :
hda: cache reads 135 MB/s
hda buffered reads 40 MB/s

hde: cache reads 135 MB/s
hde buffered reads 45 MB/s

hdg: cache reads 135 MB/s
hdg buffered reads 45 MB/s

bonnie++ målinger :
|-------------------+--------+-------+-------+-------+-------+-------+-------+-------|
|Tested device      |Char    |CPU    |Block  |CPU    |Char   |CPU    |Block  |CPU    |
|transfer in KB/s,  |write   |load   |write  |load   |read   |load   |read   |load   |
|load in %          |        |       |       |       |       |       |       |       |
|-------------------+--------+-------+-------+-------+-------+-------+-------+-------|
|Hda7               |   17129|     95|  26056|      9|  17102|     86|  38483|      4|
|-------------------+--------+-------+-------+-------+-------+-------+-------+-------|
|Hde7               |   16799|     94|  39806|     14|  17593|     89|  44300|      6|
|-------------------+--------+-------+-------+-------+-------+-------+-------+-------|
|Hdg7               |   17374|     96|  40673|     14|  17875|     91|  45432|      5|
|-------------------+--------+-------+-------+-------+-------+-------+-------+-------|
|Raid0 (hde20 +     |   17143|     95|  44183|     16|  17950|     92|  45590|      7|
|hdg10)             |        |       |       |       |       |       |       |       |
|-------------------+--------+-------+-------+-------+-------+-------+-------+-------|
|Raid5 (hda6 + hde6 |   15525|     85|  36373|     13|  17667|     91|  55898|     10|
|+ hdg6)            |        |       |       |       |       |       |       |       |
|-------------------+--------+-------+-------+-------+-------+-------+-------+-------|



Så ændrede jeg hard diskene fra 16 bit mode til 32 bit mode og kørte
testene
igen.
|---------------------+---------+------+-------+------+-------+------+-------+------|
|With 32 bit IO       |Char     |CPU   |Block  |CPU   |Char   |CPU   |Block  |CPU   |
|enabled (hdparm -c1) |write    |load  |write  |load  |read   |load  |read   |load  |
|---------------------+---------+------+-------+------+-------+------+-------+------|
|Hda7                 |    17576|    96|  29927|    10|  17191|    86|  39357|     5|
|---------------------+---------+------+-------+------+-------+------+-------+------|
|Hde7                 |    17588|    96|  41898|    15|  18353|    92|  45663|     5|
|---------------------+---------+------+-------+------+-------+------+-------+------|
|Hdg7                 |    17594|    96|  41985|    15|  17187|    86|  45957|     4|
|---------------------+---------+------+-------+------+-------+------+-------+------|
|Raid0 (hde20 + hdg10)|    17586|    96|  47989|    17|  18592|    94|  46019|     6|
|---------------------+---------+------+-------+------+-------+------+-------+------|
|Raid5 (hda6 + hde6 + |    15727|    87|  40422|    15|  18388|    93|  67075|    11|
|hdg6)                |         |      |       |      |       |      |       |      |
|---------------------+---------+------+-------+------+-------+------+-------+------|




Jeg er forundret (og skuffet) over performance af mit raid 0 især.
Jeg kan ikke lige huske hvilken block størrelse jeg har lavet på mit raid
0, men kan det forklare det alene
hvis nu den er lavet for lille ?

Er der nogen som kan give et bud på hvad der er galt ?


Her er lidt mere info om mit system :

ASUS P4B533-E motherboard with
512 MB ram
Onboard Promise fasttrak IDE Raid controller PDC 20276 (bios software
based)
Onboard EIDE controller
Plextor CD-RW/DVD Combo drive
Two IBM 80 GB disks, One Maxtor 80 GB disk
Nvidia Gforce graphics card
IEEE 1394 interfaces
USB 2.0 interfaces

Mandrake 9.1 Linux based on 2.4.21-013mdk kernel with one
change in kernel configuration namely disabling the promise
raid feature in order to use the promise controller as
an ordinary IDE controller.

Mvh
Lars Olesen
B,Sc,E,E
DSP SW designer
Bang & Olufsen
Peter Bangs Vej 15
DK-7600 Struer
Denmark

Phone       (+45) 96 84 4359
Fax   (+45) 96 84 44 01
e-mail:     lol@xxxxxxxxxxxxxxx