It looks like parity dramatically slows down the array because it has to read the drive first, write to it, then update the parity.  Can I disable parity while building the array?  I could easily copy data simultaneously (I think) to all 4 drives at much faster speeds.

 

Right now it is looking like 5 days to complete the migration and I could really use about 1 day of wait if possible.

My source is a 16-spindle hardware RAID6 array that can easily deliver 500MB/sec simultaneous read+write.

You can't simply "disable" parity ... but can do a "New Config" and simply not assign a parity drive.

 

Be SURE you know which drive is the parity drive ... and just assign your data drives to the new array.    Then you can copy data to the array and it will, as you've noted, be MUCH faster.

 

When you're ready, just Stop the array; assign the parity disk; and let it do a parity sync.  When that's done, do a parity check to confirm all went well.

 

Note, however, (as you probably already know), the you'll be running "at risk" while you're copying all your data to the array [i.e. no fault-tolerance] ... so be sure you have good backups of all your data (as you should anyway, of course).

 

All my data is on a 16-spindle and 24-spindle massive RAID6 arrays in two separate states, with critical data also offline backed up.

 

Can I do this through the web UI?  I can't figure out how to destroy my existing array and start over, or how to re-format drives.  In the GUI I mean.

Sure, just unassign the parity drive and set a new config.

 

Be aware that you will not be fault tolerant until you calculate parity.

 

You should always keep backups of your data, but be extra careful to keep things backed up until the array is fully populated and working well.

 

Unraid is not a speed demon, it is a cheap way to get a fault tolerant network mass storage device with almost any modern hardware, mix and match drives, etc.

How do I unassign the parity drive?

On the Utils tab just click on New Config => then set a new configuration that does not include a parity drive.

 

How do I unassign the parity drive?

Stop the array, pull down the parity slot and set it blank, then set a new config.

Perfect.  I did this and it worked great.  Is there a way to reformat the drives? They seem to be holding on to the old data, I'd like to start with them freshly formatted.

Perfect.  I did this and it worked great.  Is there a way to reformat the drives? They seem to be holding on to the old data, I'd like to start with them freshly formatted.

 

You could simply delete all the current files => this would leave the array intact.

 

Or boot to any good partition management tool and delete the existing partitions from the drives; then do another New Config.    The drives will now show as "Unformatted" ... formatting will just take a couple minutes; then you'll have a nice, new, EMPTY array 

 

You could also use the Linux fdisk command from the console.  Just Stop the array, and then use fdisk at the console.    I'm not sure exactly what options you'd need to do this ... I'm not a "Linux guy" 

 

http://www.cyberciti.biz/faq/linux-disk-format/

It is disabled and now I have all 4 drives copying data over.  I'm hoping it ends up going 4 times faster or more, if so it should be able to complete sometime tomorrow.

It is disabled and now I have all 4 drives copying data over.  I'm hoping it ends up going 4 times faster or more, if so it should be able to complete sometime tomorrow.

 

Not likely to go 4 times faster => that would be faster than a Gb network can transfer data 

[Assuming you had a mid-30's rate with parity enabled ... which is what I'd have expected]

 

But it should be more than 3 times as fast anyway.