[Soekris] Harddisk Slow

[Heinrich Rebehn]

Igor Sobrado wrote:
> In message <1816282B-B315-4DE7-B13F-EFE507FB9CD2 at ctrlsft.com>, Steven Finnegan writes:
>> Heinrich:
>>
>> When using DD, it is important that you set the buffer size.  
>> Otherwise you end up transferring ONE sector at a time, which is very  
>> inefficient.
> 
> bs is the block size, not the buffer size.  It is, however, an useless
> parameter if the filesystem is not tuned to use that block size on all
> transactions by means of newfs.  A block size of 1024KB is probably
> not supported, and certainly not recommended for a general purpose
> filesystem (a fragment size of 128KB is certainly a waste of space
> for most filesystems, perhaps it will work for databases).  On a FFS,
> the default block size is 16KB.
> 
> Cheers,
> Igor.

Actually, using 32K as block size speeds up dd's throughput from 8 to 
18MB/s, yet the CPU usage remains ~90% sys.

--Heinrich