linux hd speed

[V13]

On Sunday 14 December 2003 16:49, Antonis Sidiropoulos wrote:
> basika, profanws den me noiazei i akribeia.
> Apla exw 2 diskous (enan scsi palio kai enan ata66)
> kai thelw na dw sto peripou apodosi sto sygkekrimeno mixanima.
> px. x kb / sec read, y kb/sec write gia ton kathena mia tyxaia xroniki
> stigmi,
> kai dedomenou to ti yparxei sto disko kai to fragm.
> profanws an oi apodoseis einai konta den mporeis na sygkrineis.
> an omws to ena einai 10 kai to allo 100, tote yparxei diafora...
> as einai kai cached read/writes auto pou metraw. den me peirazei.

Tote mporeis na kaneis 2-3 test... 

a) hdparm gia read/writes xoris cache 
b) time /bin/bash -c 'dd if=/dev/zero of=koko bs=1024 count=102400; sync'
c) An exeis 2.6 kernel na prokaleseis megalo i/o (seiriako kai mh seiriako) 
kai na trexeis taytoxrona top h vmstat oste na blepeis kata poso o 
epeksergasths analonetai se i/o wait...

An o scsi diskos soy den einai para poly palios tote gia random access tha 
exeis poly kalytera apotelesmata me 0 cpu usage kati poy den isxyei gia toys 
IDE.

> A.
<<V13>>