Adding Hard Drives - A Question About Clearing (5.0-rc6-r8168)

[lungnut]

I've recently replaced a lot of my hardware in order to be able to use 3TB drives. After upgrading to 5.0-rc6-r8168, I replaced my 2TB parity drive with a brand new 3TB drive. After that process finished (roughly 10 hours), I added two more brand new 3TB drives and my old 2TB drive and started the array.

 

The WebUI reported that it was "spinning up all drives...clearing drive15 drive16 drive17" and I could see that there was disk activity via the LED's on my Norco 4220. It's been roughly seven hours and (I suppose) the process is still ongoing, but the WebUI is unresponsive and there is no status report of the clearing process. Is this normal? There is still disk activity (albeit on just drive17 at this point). How long should I expect this process to take?

 

Thanks for any answers. I used the forum's search function, but there was surprisingly few questions about this particular process (most seem to use a preclear addon tool).

 

 

[Joe L.]

I've recently replaced a lot of my hardware in order to be able to use 3TB drives. After upgrading to 5.0-rc6-r8168, I replaced my 2TB parity drive with a brand new 3TB drive. After that process finished (roughly 10 hours), I added two more brand new 3TB drives and my old 2TB drive and started the array.

 

The WebUI reported that it was "spinning up all drives...clearing drive15 drive16 drive17" and I could see that there was disk activity via the LED's on my Norco 4220. It's been roughly seven hours and (I suppose) the process is still ongoing, but the WebUI is unresponsive and there is no status report of the clearing process. Is this normal? There is still disk activity (albeit on just drive17 at this point). How long should I expect this process to take?

 

Thanks for any answers. I used the forum's search function, but there was surprisingly few questions about this particular process (most seem to use a preclear addon tool).

Now you know why the preclear tool was developed.

 

Most disks can be written at roughly 100 MB/s on the outer cylinders to less than 75MB/s on the inner cylinders.

 

Since you have three disks being written, they will share the I/O on the bus, so it might be closer to 50MB/s overall.

 

At 100MB/s you'll write 1GB every 10 seconds.  At 50MB/s, it will take 20 seconds per GB.

 

Your 3TB drives have 3000 GB to write.

 

3000 * 10 seconds = 30,000 seconds, or 500 minutes, or 8.33 hours.  (assuming the 100MB/s rate)

3000 * 20 seconds = 60,000 seconds, or 1000 minutes, or 16.66 hours.  (assuming you can keep up the50MB/s rate)

 

You'll be up and running somewhere between 8.33 and 16.66 hours (my best guess)

 

In my house, having the server go off-line for an evening when just installing a new disk will make me very un-popular.    I ALWAYS preclear the drives, first to make sure I have little down-time, and equally important, to eliminate some of the risk of an early disk failure.  (They will often fail in the preclear, instead of after being installed and assigned to the array)

Joe L.

[lungnut]

 

You'll be up and running somewhere between 8.33 and 16.66 hours (my best guess)

 

In my house, having the server go off-line for an evening when just installing a new disk will make me very un-popular.    I ALWAYS preclear the drives, first to make sure I have little down-time, and equally important, to eliminate some of the risk of an early disk failure.  (They will often fail in the preclear, instead of after being installed and assigned to the array)

Joe L.

 

You were right on. Thanks, Joe. And I will definitely preclear next time.