I am starting a new unRaid server 4.5.1 using SATA drives (I have a older PATA unRaid from back in the early days when unRaid was first starting).  I have 3 drives, 2 of which I ran full manufacturer diagnostics on and used the manufacturer's diags to write zeroes to the drives (so that any bad sectors can be reallocated).  I assigned these 2 drives as data drives and they showed up as unformatted as expected.  Clicked on start array and started formatting.  Came back after about 15 min and clicked refresh and it showed that the disks were in the array and green (show a few hundred writes).  Shouldn't it have taken alot longer to clear the drives? (unRaid shouldn't have recognized the zeroed drives as cleared, right?, it should do its own clear).

 

Copy a few gig of data over to each of the two data drives.  Assigned the 3rd drive (which was not cleared by any manufacturers diags) as the parity.  Started array and the parity drive showed up as unformatted.  Formatted and started a parity sync and it is presently running. 

 

This is just a test of setting up a new server since it has been years since I started my first server which was built with data and parity assigned from the beginning.

 

So my questions.  I am using 3 500G drives.

Even if the drives have been zeroed by a manufacturer's diag, unRaid should still clear the drives? (i just saw something about the preclr script)

 

Parity drive doesn't need to be cleared since the array sync will overwrite parity data (up to the size of the largest data drive)?

 

Thanks.. Ed

 

 

 

I am starting a new unRaid server 4.5.1 using SATA drives (I have a older PATA unRaid from back in the early days when unRaid was first starting).  I have 3 drives, 2 of which I ran full manufacturer diagnostics on and used the manufacturer's diags to write zeroes to the drives (so that any bad sectors can be reallocated).  I assigned these 2 drives as data drives and they showed up as unformatted as expected.  Clicked on start array and started formatting.  Came back after about 15 min and clicked refresh and it showed that the disks were in the array and green (show a few hundred writes).  Shouldn't it have taken alot longer to clear the drives? (unRaid shouldn't have recognized the zeroed drives as cleared, right?, it should do its own clear).

 

Copy a few gig of data over to each of the two data drives.  Assigned the 3rd drive (which was not cleared by any manufacturers diags) as the parity.  Started array and the parity drive showed up as unformatted.  Formatted and started a parity sync and it is presently running. 

 

This is just a test of setting up a new server since it has been years since I started my first server which was built with data and parity assigned from the beginning.

 

So my questions.  I am using 3 500G drives.

Even if the drives have been zeroed by a manufacturer's diag, unRaid should still clear the drives? (i just saw something about the preclr script)

 

Parity drive doesn't need to be cleared since the array sync will overwrite parity data (up to the size of the largest data drive)?

 

Thanks.. Ed

 

 

 

unRAID does not need to clear a newly added drive to retain parity protection until you assign a parity drive.  Therefore, so far, the drives you have assigned have not been cleared at all, they've just been partitioned (takes less than a second) and formatted (takes less than a minute) with as you've discovered, just a few hundred writes to set up the formatting.

 

If you had assigned a parity drive first, the array would have spent many hours clearing the disks.  Sine you assigned it last, there was no need to ensure the disks were zeroed to maintain parity, so, no clearing was performed.

 

The parity disk does not have a file-system.  It is probably a bug that it had the "unformatted" description, as it never is formatted.  In any case, the parity calculations would overwrite anything on the parity disk even if you did format it. 

 

be very careful if you see the "Format" button.  some have reported disk showing as un-formatted when they have already been formatted and loaded with data. Stopping and re-starting the array will get it to recognize the disks properly.  In general, un-formatted simply indicates the drive cannot be mounted as a reiserfs file-system, or that the disk is not partitioned as expected.  A drive that takes longer to initialize is probably why some have reported the "un-formatted" screen indication.  Just do not press the "Format" button in that situation,  it is there in error, and pressing it will format the disks showing as unformatted. (this causes hair-loss and tears)

 

You've missed the opportunity to use the pre-clear script to burn-in the drives to exercise them and test them for any early signs of any problems.  The pre-clearing cannot be performed on a disk assigned to the array.    If you do wish to burn in the drives you'll need to un-assign them from the array.    (obviously, you'll erase all data on them, so don't do it if you've already migrated your data)

 

The parity calculations are made to the full size of the parity drive, even if all the data drives are smaller.  It does go WAY faster once you get above the size of the data drives as it no longer needs to read them.

 

Joe L.

Thanks JoeL

 

I may have been in error when I said that the parity drive said unformatted, I was lost in thought as to why the "clearing" of the data drives was not occuring.  Your explanation makes sense.  I was just testing to see how fast data transfers would be without a parity drive.  I will rebuild the array from scratch anyway so I'll give your script a try, as it also verifies the disk surfaces (which was what I was doing with the surface scans and zero wipes using the manufacturers diags--I can cut this step out).

 

Ed

unRAID does not need to clear a newly added drive to retain parity protection until you assign a parity drive.  Therefore, so far, the drives you have assigned have not been cleared at all, they've just been partitioned (takes less than a second) and formatted (takes less than a minute) with as you've discovered, just a few hundred writes to set up the formatting.

 

If you had assigned a parity drive first, the array would have spent many hours clearing the disks.  Sine you assigned it last, there was no need to ensure the disks were zeroed to maintain parity, so, no clearing was performed.

 

I'm starting new with unRAID, and had the same question as the OP.  I am starting off with 2 x 2TB and 2 x 1TB drives.  Installed my first 2TB as data (no parity since the other 2TB drive has the data needing to be migrated from an HFS+ filesystem) and there was no clear done on the drive, so you have answered my question as to why.  No data has been migrated yet, so last night's initial setup was a quick test run of the hardware, etc.

 

Tonight, I plan on trying out the preclear script for my brand new data drive, but should I also run the script on the parity drive too?  Being parity, every block is written anyway, but would the preclear script help reallocate bad blocks, etc for proper burn in or is this an automatic process simply by being used as parity?

 

j.metts

You are correct in that the parity drive is written to entirely.  The parity drive does not even have a FS on it, like the rest of the disks in the array.

 

With that said though, I think it is a good idea to run the parity drive through at least 1 cycle of the preclear script.I usually run 2-3 depending on the results that some back to me.