Cancel / stop disk clear?

[barbapapa]

I just fouled up and added a drive that was in my machine for awhile but not in my array.  I was SURE I had already precleared the drive... but apparently I hadn't; when I added the drive, Unraid showed "Clearing" next to the new disk, and now my array is offline, unraid shows "Starting, clear 2% complete...".  I see no "stop", "cancel" or anything like that so I'm looking at a lot of offline time.  Argh.  Annoying thing is, I didn't even need this drive added yet... but I did need my array. 

 

Is there any way to cancel via the command line or something?  Every other drive I've ever added to my array was precleared, so I've never seen this before and have no idea how to stop it. 

[Joe L.]

I just fouled up and added a drive that was in my machine for awhile but not in my array.  I was SURE I had already precleared the drive... but apparently I hadn't; when I added the drive, Unraid showed "Clearing" next to the new disk, and now my array is offline, unraid shows "Starting, clear 2% complete...".  I see no "stop", "cancel" or anything like that so I'm looking at a lot of offline time.  Argh.  Annoying thing is, I didn't even need this drive added yet... but I did need my array. 

 

Is there any way to cancel via the command line or something?  Every other drive I've ever added to my array was precleared, so I've never seen this before and have no idea how to stop it. 

If you "kill" it you'll be faced with a full parity calculation.

 

There is no graceful way to stop it in the middle other than forcefully powering down the server, or killing the emhttp proceses, then re-starting it.  Either way you'll be faced with a full parity calculation.

 

You've discovered why many of us pre-clear the drives. (besides it burning in the drives before trusting them to our data)

 

Most drives are written to (cleared) at a rate between 50 and 100 MB/s.  At 100 MB/s it takes 10 seconds to clear 1 Gigabyte.  That equates to 20,000 seconds to clear 2,000 Gigabytes.  Doing the math.... your server should have its disk cleared in about 5.5 to 11 hours and it will be un-available for that duration.    (When unRAID was first released 5 years ago it used to take 1/4 of that time, but then the biggest disk on the market was 500Gig.)

 

Joe L.

[wsume99]

That equates to 20,000 seconds to clear 2,000 Gigabytes.

How do you know that he's adding a 2TB drive?

 

Most drives are written to (cleared) at a rate between 50 and 100 MB/s.  Doing the math.... your server should have its disk cleared in about 5.5 to 11 hours and it will be un-available for that duration.

My WD20EARS cleared at an avg rate of 72 MB/s for a total time of 7:38:57.  I saw another user post his info from clearing the exact same drive and he got 88 MB/s for 6:18:42.  I guess I got a slow drive :'(.

[barbapapa]

Thanks guys.  I really really thought I had already precleared that drive.  I guess I should have made sure and did "another" preclear to be sure, especially since I didn't actually need it yet.

 

That'll learn me. 

 

Now I love that preclear script even more, now that I have experienced firsthand what happens without it!

[Joe L.]

Thanks guys.  I really really thought I had already precleared that drive.  I guess I should have made sure and did "another" preclear to be sure, especially since I didn't actually need it yet.

 

That'll learn me. 

 

Now I love that preclear script even more, now that I have experienced firsthand what happens without it!

You can use the "-t" option  to the pre-clear script to have it test if a drive is already pre-cleared. It only takes a few seconds to run.

 

preclear_disk.sh -t /dev/sdX

 

Now you know why I wrote the pre-clear script.  My wife and I really use our server, any extended outage would be noticed.

 

Joe L.