Hi all, I've got a full array of 6 drives so it is time to replace the smaller ones with larger capacity models. My parity drive is large enough it does not need to be replaced.

 

My motherboard only has 6 SATA ports and my new drive is not yet precleared.  What is the best method for replacing a single drive?

Preclearing is good for testing a drive but not required when replacing a drive. Having said that I recommend preclearing. You may be able to do it with a USB enclosure if you don't have any SATA ports. Or you can run some other extensive drive tests on another sytem. The drive manufacturer may have something that will work for this.

 

To replace a disk, all you have to do is stop, shutdown, replace the disk, boot, assign the new disk to the slot the replaced disk was in, start and unRAID will rebuild the old disk contents to the new disk. Recommend a non-correcting parity check afterwards just as a test that all went well.

Preclearing is good for testing a drive but not required when replacing a drive. Having said that I recommend preclearing. You may be able to do it with a USB enclosure if you don't have any SATA ports. Or you can run some other extensive drive tests on another sytem. The drive manufacturer may have something that will work for this.

 

To replace a disk, all you have to do is stop, shutdown, replace the disk, boot, assign the new disk to the slot the replaced disk was in, start and unRAID will rebuild the old disk contents to the new disk. Recommend a non-correcting parity check afterwards just as a test that all went well.

 

Thanks for the tip! I bought the drive "used good condition" from Amazon Warehouse so I should probably run an in depth SMART at a minimum or preclear.

 

Other question, I've currently got a WD Green drove as my parity drive, but this new one is a WD Red. Any reason to use the red as the parity and expand my system with the green instead?

 

Other question, I've currently got a WD Green drove as my parity drive, but this new one is a WD Red. Any reason to use the red as the parity and expand my system with the green instead?

That would be 2 rebuilds instead of 1. As long as the Green is at least as large as the Red I probably wouldn't bother. Any performance difference is likely to be negligible.

Note that doing a rebuild, followed by a confirming parity check (this is the one time I agree that a non-correcting check is best) will test the drive well just from the process, so I'd just do a SMART check before proceeding and then do the replacement.    Should anything go awry, you still have the original (smaller) drive, so there's no risk to your data.

 

Thanks for the replies folks. I'll just pop it in and wait for a few days

 

Can I continue writing to the array through this process?

While you CAN use the array during a rebuild, I would NOT do so.    Using the array during the rebuild will slow down the process significantly ... and may eliminate the ability to simply replace the old drive should anything go awary.

 

I'd simply Stop the array; unassign the drive you plant to replace;  Start the array (so it shows the drive as "missing");  then shut down; replace the drive with the new (larger one);  boot; assign the new drive in place of the old one; and Start the array, which will start the rebuild.    Wait for that to finish, then do a confirming parity check ... and you're ready to go 

Not really necessary to unassign the original drive and start. You can just shutdown and replace it and unRAID will see it is missing, then you can assign the new disk to the old disk's slot and start. That's how I have always done it. The only time you would need to unassign the old drive is if you are going to leave it connected for some reason. And even then you could just change the slot assignment to use the new drive and start.

While you CAN use the array during a rebuild, I would NOT do so.    Using the array during the rebuild will slow down the process significantly ... and may eliminate the ability to simply replace the old drive should anything go awary.

 

I'd simply Stop the array; unassign the drive you plant to replace;  Start the array (so it shows the drive as "missing");  then shut down; replace the drive with the new (larger one);  boot; assign the new drive in place of the old one; and Start the array, which will start the rebuild.    Wait for that to finish, then do a confirming parity check ... and you're ready to go 

 

What about using the array during the parity check after the rebuild?

 

I'm going to replace the drive tonight before I go out of town for the weekend and therefore won't be able to start the parity check until I get back.

Disk rebuilds, including parity syncs, always read all drives at the same time in order to calculate the data for the rebuild. And parity checks always read all disks at the same time to compare parity to the other drives. In other words, basically the same answer as gary already gave. If you are doing other reads and writes at the same time then the drive heads are going to have to move around and it will have to wait for the disk to spin around to the data in order to work with the data involved with any reading or writing, and do the same to access the data for the rebuild or parity check.

 

See the wiki for how parity works. Knowing that will make many things clearer.