The WD Ultrastar DC HC520 / HGST He12 should have a transfer rate of 243MiB/sec.
This is true for the first two TBs, but than it degrades to only 50% in the center of the drive.
Used the following script to run 5 cycles. For each cycle measured the transfer rate at each start of a TB.
Each cycle showed the same transfer rate (there was no variation) at a specific TB start, independent of temperature.
SKIP=0 10.0GiB 0:00:42 [ 242MiB/s]
SKIP=1 10.0GiB 0:00:42 [ 242MiB/s]
SKIP=2 10.0GiB 0:00:43 [ 235MiB/s]
SKIP=3 10.0GiB 0:00:45 [ 226MiB/s]
SKIP=4 10.0GiB 0:00:46 [ 220MiB/s]
SKIP=5 10.0GiB 0:00:48 [ 210MiB/s]
SKIP=6 10.0GiB 0:00:50 [ 202MiB/s]
SKIP=7 10.0GiB 0:00:53 [ 192MiB/s]
SKIP=8 10.0GiB 0:00:57 [ 178MiB/s]
SKIP=9 10.0GiB 0:01:01 [ 166MiB/s]
SKIP=10 10.0GiB 0:01:08 [ 149MiB/s]
SKIP=11 10.0GiB 0:01:18 [ 129MiB/s]
RUN=1 33Celsius
RUN=2 39Celsius
RUN=3 42Celsius
RUN=4 43Celsius
RUN=5 44Celsius
Did somebody else notice this 50% drop of transfer rate for these drives?
Did you receive a sustainable transfer rate through the drive?
Hope to have some users running my script and showing their results for similar drives.
This is true for the first two TBs, but than it degrades to only 50% in the center of the drive.
Used the following script to run 5 cycles. For each cycle measured the transfer rate at each start of a TB.
Code:
#!/bin/bash
for run in 1 2 3 4 5
do
for i in 11 0 1 2 3 4 5 6 7 8 9 10 11
do
echo "RUN=$run SKIP=$i"
b=`expr 1024 \* 10`k
s=`expr $i \* 100`KB
c=`expr 1024 \* 1`
dd if=/dev/sdg bs=$b iflag=direct skip=$s count=$c status=none | pv -b -t -r >/dev/null
/usr/sbin/smartctl -a /dev/sdg | grep ^194 # show temperature
echo
done
doneEach cycle showed the same transfer rate (there was no variation) at a specific TB start, independent of temperature.
SKIP=0 10.0GiB 0:00:42 [ 242MiB/s]
SKIP=1 10.0GiB 0:00:42 [ 242MiB/s]
SKIP=2 10.0GiB 0:00:43 [ 235MiB/s]
SKIP=3 10.0GiB 0:00:45 [ 226MiB/s]
SKIP=4 10.0GiB 0:00:46 [ 220MiB/s]
SKIP=5 10.0GiB 0:00:48 [ 210MiB/s]
SKIP=6 10.0GiB 0:00:50 [ 202MiB/s]
SKIP=7 10.0GiB 0:00:53 [ 192MiB/s]
SKIP=8 10.0GiB 0:00:57 [ 178MiB/s]
SKIP=9 10.0GiB 0:01:01 [ 166MiB/s]
SKIP=10 10.0GiB 0:01:08 [ 149MiB/s]
SKIP=11 10.0GiB 0:01:18 [ 129MiB/s]
RUN=1 33Celsius
RUN=2 39Celsius
RUN=3 42Celsius
RUN=4 43Celsius
RUN=5 44Celsius
Did somebody else notice this 50% drop of transfer rate for these drives?
Did you receive a sustainable transfer rate through the drive?
Hope to have some users running my script and showing their results for similar drives.
Last edited:
