dd is so slow on my SCSI disc

Emanuel Strobl Emanuel.strobl at gmx.net
Mon Aug 22 20:33:54 GMT 2005

Am Montag, 22. August 2005 22:13 CEST schrieb Sebastian Pahlke:
> Hi all,
> I'm trying to "clean" a disc before selling them:
> dd if=/dev/zero of=/dev/da0
> Do I make something wrong because the transfer rate is only 60932
> bytes/sec??? These are 60 kbytes/sec, slower than my internet
> connection!!!
> :(
> I tried to increase the block size, with bs=32768 I get 3416071
> bytes/sec. But this is still very poor. The system is a PIII 800MHz and
> a SCSI-3 disc in single user mode booted from FreeBSD release 5.4
> live-cd.
> Any ideas how to analyze this? Thanks in advance!

Hmm, what dows systat (-vm 1) tell you? What's the disk load, maybe you're 
suffering from interrupt storms? I can't you help much with specific SCSI 
parts, but maybe you want to try 6.0-BETA3, if I remember correctly there 
were some adaptec problems fixed...


> greetings,
> Sebastian Pahlke
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