On 09/23/2014 08:31 PM, jd1008 wrote:
So, how can I ascertain if I am getting much better transfer
(read/write)
speeds without doing io from one unmounted partition of drive A to an unmounted
partition on disk B?
Usually I use dd with bs=512M or 256M (in case I have a lot of programs running).
I have seen 65 mbytes/s, but that is achievable even with UDMA133 PATA drives spinning
at 7200rpm.
Try
hdparm -t /dev/sda (if your drive is sda)
this will do a speed test reading the first part of the disk.
Consider that:
- the beginning of the disk is faster then the final part (which can be about
half speed)
- normal drives have actual physical speed from 50MB/s to 200MB/s, even if
the SATA link permits a faster speed
- your drive is a "WD Green", which are generally quite slow, do not expect
spectacular numbers
Finally, if you get significantly slower numbers for /dev/sda1 with respect
to /dev/sda, maybe your partitions are not well 4k aligned (this happens when
the partitioning tool is too old).
--
Roberto Ragusa mail at robertoragusa.it