Shrinking array, how long should it take to zero out a 4TB drive?

[flyize]

Following the writeup here: https://wiki.unraid.net/Shrink_array

 

Using dd to zero out the drive and its writing at about 1.1MB/s. At that rate, it seems the process will complete sometime around the fall of humanity. Am I doing something wrong?

[JorgeB]

Just now, flyize said:

Am I doing something wrong?

It's known issue with the scrip and current releases, it should not be used, you can still do it manually:

 

https://forums.lime-technology.com/topic/61614-shrink-array-question/?tab=comments#comment-606335

 

 

[flyize]

I have reconstruct write enabled, and am doing it manually. However, the array isn't in maintenance mode. Could that be the actual issue?

[JorgeB]

1 minute ago, flyize said:

the array isn't in maintenance mode

You can't do that with the drive mounted, parity likely won't be valid in the end, but shouldn't be the reason for the low speed, possibly it's hardware related, diags might show something.

[flyize]

I had that specific drive unmounted (that's what the advanced section of the wiki says to do). Just in case, here are diagnostics.

 

 

truffle-diagnostics-20220419-1020.zip

Edited April 19, 2022 by flyize

[JorgeB]

The array is stopped in the diags, which drive were you removing? You have some SMR drives, those can be slower, you can also run the diskspeed docker test to make sure all disks are reading at normal speeds.

[flyize]

Yeah, I started to attempt your suggestion which is why the array was stopped. The drive I'm removing isn't SMR. However, with the array in maintenance mode, I'm getting 182MB/s. That will do. Thanks!

[JorgeB]

3 minutes ago, flyize said:

with the array in maintenance mode, I'm getting 182MB/s.

That only makes sense if you were still using the array before.

[flyize]

5 minutes ago, JorgeB said:

That only makes sense if you were still using the array before.

The array was online and mounted (except the drive I was zeroing out). There isn't any mention that the array shouldn't be mounted in the wiki. Should there be?

[JorgeB]

The problem is not being mounted, but being in use, with reads or writes, that will slow down the zeroing speed by a lot.

[flyize]

Then I'd like to update the wiki to something like:

 

For best performance, make sure there are no reads/writes happening to the array. The easiest way to do this is to bring the array up in maintenance mode.

 

Does that make sense? Had *I* known that, I'd have already had the old drive removed and the new drive replaced days ago.