parity swap???

[jbuszkie]

I'm running beta 11 and I thought there was an automatic way to assign the new 3TB drive as parity and have the old 2TB be

drive.  I thought I remembered reading something about a  parity swap that would be done automatically..  I can't find it though..

 

Is there a different procedure for parity swap with the 5.x betas?

 

THanks,

 

Jim

[dgaschk]

http://lime-technology.com/wiki/index.php?title=UnRAID_Manual#Replace_a_single_disk_with_a_bigger_one

[jbuszkie]

I thought there was a way to do it on one step?  It would add the old parity disk as a data disk in the same step as adding the parity.  Maybe a beta 5 feature?  was I just imagining it??

 

Jim

[Joe L.]

I thought there was a way to do it on one step?  It would add the old parity disk as a data disk in the same step as adding the parity.  Maybe a beta 5 feature?  was I just imagining it??

 

Jim

It can ONLY be used if the data disk has FAILED and been marked as INVALID.

[WallaceTech]

Sorry to Hijack.

 

Are you saying that any parity disk i use in the future can never be taken out and used as a data disk?

 

I was looking to upgrade my parity to a 2TB disk and then when the time is right to 3TB disk. My plan was to remove the 1TB parity, upgrade to 2Tb and then use the 1TB in my array.

 

Are you saying this is not possible? If this is true then i may need to question unRaid as my solution

[jbuszkie]

You certainly can use an old parity disk as a data disk...  but it's a two step process!

[prostuff1]

Sorry to Hijack.

 

Are you saying that any parity disk i use in the future can never be taken out and used as a data disk?

 

I was looking to upgrade my parity to a 2TB disk and then when the time is right to 3TB disk. My plan was to remove the 1TB parity, upgrade to 2Tb and then use the 1TB in my array.

 

Are you saying this is not possible? If this is true then i may need to question unRaid as my solution

That is possible to upgrade the parity drive to a larger size.

[WallaceTech]

Thanks for the confirmation guys. Phew!!!

 

[jbuszkie]

So I guess that mean I have to preclear the old parity drive before it can go into the system (quickly)

 

Jim

[dgaschk]

No. Rebuilding does not require a clear drive. Every bit on the disk is written.

[daniel.boone]

There is a special process for replacing the parity with a larger drive when a smaller array drive has failed. I just did this with B13. While I did not lose data the process did not go smoothly. I'm happy to share how I did it but it sounds like you want something else.

[jbuszkie]

No. Rebuilding does not require a clear drive. Every bit on the disk is written.

  That's not what I was referring to..  I was referring to putting my old disk back in service as

a data disk.  I assume now I have to preclear it if I want to quickly add it to the array!

 

It would be nice if UnRaid would see that I wanted to add a bigger disk as a data disk and allow me to swap the bigger disk as the parity and

make the old disk a data disk at the same time!  Now I had to create the new parity disk with the parity synch (which finished Yeah!) and now I have my old parity disk which I now have to pre-clear to add it to the array (if I want to do it quickly)

 

Jim

[husky55]

I am new at this, How long does it take for the parity-sync to complete if  a 2tb parity drive was replaced by a 3tb  drive? I am talking about a cpu i3 540 with 2 GB ram.

[jbuszkie]

I am new at this, How long does it take for the parity-sync to complete if  a 2tb parity drive was replaced by a 3tb  drive? I am talking about a cpu i3 540 with 2 GB ram.

  I don't know the exact time. But it was somewhere between 8 and 12 hours

And my cpu is not a strong as yours.

[Joe L.]

I am new at this, How long does it take for the parity-sync to complete if  a 2tb parity drive was replaced by a 3tb  drive? I am talking about a cpu i3 540 with 2 GB ram.

  I don't know the exact time. But it was somewhere between 8 and 12 hours

And my cpu is not a strong as yours.

CPU has little to do with it.

 

A drive can be written at roughly between 60 and 100MB/s.  (Most will start at the higher rate and slow as they get to inner cylinders)

 

At 100MB/s, it will take 10 seconds per Gigabyte.  That is 6GB per minute.

At 60MB/s it will take 16.66 seconds per Gigabyte.  That is 3.6GB per minute.

 

A 3TB drive is 3000GB.  3000GB / 6GB per minute = 500 minutes.

500 minutes = 8.3 hours.

 

at the slower rate,  3000GB / 3.6GB per minute = 833 minutes.

833 minutes = 13.88 hours.

 

So, best possible case is over 8 hours, a more realistic number is probably closer to the 13.88 hour mark.

 

Note that these numbers are without having to read all the other disks and calculate parity... Fortunately, unless you are limited by the bus speed to your disk controllers, it is done in parallel.  You are basically limited mostly by the write speed to the parity drive.  The amount of RAM and CPU have very little bearing on the time...  the process uses very little CPU. 

 

Joe L.

[husky55]

Thank you for the tutorial. I just checked the price of the 3 TB. My upgrade just have to wait, the price quoted are just unreal. Having just survived tropical storm Irene and then the crazy Alfred snow storm, I really feel for the Thailand people with their flood.