[Soekris] Harddisk Slow
rebehn at ant.uni-bremen.de
Wed Jan 31 11:55:35 UTC 2007
Igor Sobrado wrote:
> In message <1816282B-B315-4DE7-B13F-EFE507FB9CD2 at ctrlsft.com>, Steven Finnegan writes:
>> 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
> 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.
Actually, using 32K as block size speeds up dd's throughput from 8 to
18MB/s, yet the CPU usage remains ~90% sys.
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