I am just rebuilding my main array as that's sort of thing I seem to like to do in my spare time! These drives are the same drives that were used in unraid for about 2 years now and i am wondering if this activity is usual when writing data, i don't recall so many reads happening when I'm writing.

 

I didn't preclear the drives this time, just used gparted to reset the GPT to empty and then unRAID itself to format the drives as they are known good.

 

All the writes are happening via samba using the mc program from the console of unRAID.

 

The initial parity check will cause writes to EVERY sector on the parity disk.

 

In addition, if you assign a disk to an array that already has a parity disk assigned, UnRAID will clear EVERY sector of the new disk.    When you reset the disk, then UnRAID would need to do that, and this would  cause a large number of writes to that disk.

 

Once your array's initialization is completed, the write counts will be "normal" (as you're accustomed to).

 

The initial parity sync has already completed...

 

I mean I'm only 100Gb into refilling at 12tb array so can easily blow things away again if I've made a basic mistake (which I didn't think I had!). I added all 5 disks at once, all completely unformatted with an empty GPT, so why does it need to clear EVERY sector as you describe?

 

Is this also why I'm only getting write speeds around 20mbs or so, usually a steady 40 or so.

 

I cleared the stats after the initial party sync, hence why disk 2 has no stats...

 

Am I best running each drive though the preclear script but with the options for 'stressing' the drives disabled?

...so why does it need to clear EVERY sector as you describe?

...

Parity disk uses every sector and every sector of each data disk has to match so unused sectors are cleared.

...so why does it need to clear EVERY sector as you describe?

...

Parity disk uses every sector and every sector of each data disk has to match so unused sectors are cleared.

 

 

Oooo right, light bulb.

 

So not preclearing the drives leads to this and i will continue to suffer from this problem until the entire array is full. Bummer.

 

Sent from my Nexus 5 using Tapatalk

 

Right, I'm pre-clearing all drives now in an effort to keep my sanity. 20mb/s writes are ludicrous with my hardware!

If you add ALL of the data drives BEFORE you add a parity drive, then they won't need to be cleared.    It only has to clear drives that are added to a parity-protected array.

 

So if you want to avoid this in the future, add all your data drives;  Start the array and let them format;  then Stop the array, add parity, and Start it back up.  It will do the initial parity sync, and you'll be done      (No clearing involved)

 

Thanks dude.

 

Pretty sure I added all the drives at the same time, but a zeroing can't hurt them. They're all still in warranty so will do them some good no doubt. 3TB drives take about 30hrs to clear though! Oh well.

 

See you tuesday.

Sorry, please ignore, a 3 year old got ahold of my phone and managed to post.

 

Sent from a mobile device, sorry for any typos.

 

Turns out a I hadn't 4k aligned the partitions. Now getting write speeds (without parity attached yet) of 90+mb/s. Certainly an improvement. Will be interesting to see what differences occur when I add the parity speed wise.

Turns out a I hadn't 4k aligned the partitions. Now getting write speeds (without parity attached yet) of 90+mb/s. Certainly an improvement. Will be interesting to see what differences occur when I add the parity speed wise.

Wow, that's interesting. If this is a test mule system, would it be too much to ask of you to change your drives back one at a time to unaligned and see what happens speed wise? I was under the impression that 4K alignment was nice, and forward thinking, but not required for max performance except for a very few drive models.

 

I would be really interested to see what happens if a single drive is unaligned.