Low HDD tranfer rate with FreeBSD 5.3-Release

Amandeep aman at chamkila.org
Mon May 9 12:42:17 PDT 2005


Amandeep wrote:

> Dan Nelson wrote:
>
>> In the last episode (May 09), Eric Anderson said:
>>  
>>
>>>> Eric Anderson wrote:
>>>>     
>>>>
>>>>> Amandeep wrote:
>>>>>       
>>>>>
>>>>>> I am using Tyan S2098 MB with 160GB Maxtor ATA  Drive and the
>>>>>> transfer rate is very low. FreeBSD 5.3-Release.
>>>>>> Any ideas what is going on here.
>>>>>>
>>>>>> The transfer rate is about 15MB/s
>>>>>>
>>>>>> when I run
>>>>>> #dd if=/dev/zero of=/usr/junk bs=8192
>>>>>>         
>>>>>
>>>> Shouldnt it be around 54MB/s for a regular IDE drive.
>>>>     
>>>
>>> What about other block sizes?  Also - you should paste your actual dd
>>> output here too.
>>>
>>> What's the model number of that drive?  Maxtor claims (on one of
>>> their 160G drives) 17.8MB/s from inner diameter disk and 35.6MB/s for
>>> outer diameter for the 5400rpm drives.
>>>   
>>
>>
>> Yes, try 64k instead of 8k, and also compare read speeds.  If you have
>> the time (could take an hour or so), try "dd if=/dev/ad0 of=/dev/null
>> bs=64k", run an "iostat 60" in another window, let the dd run through
>> the entire disk, and compare the relative speeds from start to finish.
>>
>> For the DiamondMax 160, the sustained throughput should be 26MB -> 50MB
>> as you go from inner to outer tracks.
>>
>>  
>>
>
> OK with the above dd
>
> dd if=/dev/ad0 of=/dev/null bs=64k
>
> it gives me 56MB/s. from the start.
>
> Aman

So how does the block size makes the difference?? What is the true 
transfer rate.?

Aman

>
>
> _______________________________________________
> freebsd-questions at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-questions
> To unsubscribe, send any mail to 
> "freebsd-questions-unsubscribe at freebsd.org"
>



More information about the freebsd-questions mailing list