hi everybody,

i am currently preclearing a WD 2T EADS H/D and I am at the post-read stage. The speed reported by unraid (66MB/s) is half of the speed that I notice (about 33MB/s). Is there an explanations for that?

Most likely you're misunderstanding what's being reported. The performance of a drive in preclear does not equate to exact performance inside the array. Also, make sure you're not mixing up read speeds against write speeds.

 

maybe it has something to do with this:

 

when doing a parity check, my unRAID tells me "65MB/sec"

and when i look into the disc performance menu from unMenu it specifies that in reality it is of 32 MB/s reading from disc1 and 33MB/s reading from parity disc.

 

while preclearing i get pre/post read ~100MB and writing zeros with around 80-90 MB

 

 

while my system isn't running as it should, those numbers may help you out in any way.

 

Good luck

 

well,

what i see is 65 MB/sec during post read but the real speed i calculate is about 33MB/sec. But preclear doesnt access any other disk so there is no reason for the actual speed to be half the one given by the preclear tool...

The preclear display is showing you the actual drive read speed, but during the post read it is also verifying that the zeroing was successful  The unmenu speed info is actually sampling the read activity over time which includes both the disk and processing pieces. So both of your numbers are right.

thanx, that seems like a logical explanation