upgrading a drive and pre-clearing it?

[squirrellydw]

Here is my situation, my motherboard supports 6 drives and they are all being used?  What I want to do is upgrade my parity drive to a 7200 drive and use my old parity drive for storage in unraid.  I don't want to buy a add on card yet.  So heres my question.....

 

Can I take out my old parity drive, install and PRE-CLEAR the new one than activate it?  I know during this time I won't have parity activated but will this work?  I still have the old parity drive since I won't erase that one till the new one is ready to go and I won't add or change anything to Unraid till then.

 

Also if that works, after that is done can I remove an old data drive that has data on it, install the old parity drive and PRE-CLEAR it and then rebuild it?  The old parity drive is a WD GREEN EARS with a jumper.

 

Thanks, hope you understand.

[lionelhutz]

You could just not run the array while you are pre-clearing. Then your old parity would still be available for recovery in case another drive did fail.

 

But you are right, if you run the array without the parity and do not write to the array you could recover from a disk failure. It's not a great way or easy way to recover through and assuming all goes well you might only lose a few files. I would recommend you just suck-up the 25 hours without the array and run the pre-clear with the array stopped.

 

You could also scrounge up any other PC and create a free unRAID flash drive and then use it for the pre-clearing.

 

I would not bother pre-clearing the old parity. It's been in the system working for a while now so there should be no need to stress test it. Just put it in the data drive slot and let unRAID rebuild the data onto it.

 

Peter

[squirrellydw]

So your saying I should just STOP the array and leave it that way while pre-clearing?  Never thought of that.

The reason I wanted to pre-clear the old parity drive was so I could remove the jumper from the WD GREEN EARS drive.

[lionelhutz]

You won't break the parity protection if you do the preclear with the array stopped.

 

It is pointless to remove the jumper from the EARS. Just keep using it as is.

 

Peter

[Joe L.]

You won't break the parity protection if you do the preclear with the array stopped.

 

It is pointless to remove the jumper from the EARS. Just keep using it as is.

 

Peter

And if you do keep the jumper in place, and I recommed you do, do NOT use the -A option to the preclear script.  

Instead, for a jumpered EARS drive you want to use the "-a"  option  (lower case "a")

preclear_disk.sh -a /dev/sdX

where sdX =  the device name of the jumpered EARS drive.

 

Make sure you use the newest version of the preclear script.  There have been many improvements in the past few days.

 

Joe L.

[squirrellydw]

Well I plan on doing this in two to three weeks.  So i should stop the array, unassign the parity drive, power it off, put the new parity drive in, power it on, pre-clear it then assign it as parity right?

 

Joe, I will leave the jumper since you recommend it but why do you recommend that?  If I buy a new EARS drive what do you suggest?

 

Thanks

 

 

[squirrellydw]

bump

[SSD]

Seems a lot of trouble.

 

I would do one of three things:

 

1 - Upsize the smaller data drive with the new disk (which you could preclear in another machine) and be done with it

 

2 - Copy the data from the 500G to other disks on the array (or on a workstation).  Then power down, remove the 500G disk, install your new disk (precleared in another machine or preclear it now), power up, stop array (if it starts), run initconfig, rearrange disks (establish new disk as parity, old parity as a data disk), and rebuild parity.  If you don't write to any of your data disks (including the 500G you pulled) and don't format parity, you would be able to put humpty dumpty back together again to do a disk restore should you need to.  Once parity is rebuilg, format old parity (now a data disk) and copy data from 500G disk here.

 

3 - Of course the best option is to buy a cheap 2 port PCI or PCIe card.  You should never have every port in use by an array IMO.

[squirrellydw]

OK, I guess I will order the drive and this card and make it easy on myself.

 

http://www.newegg.com/Product/Product.aspx?Item=N82E16816101358

 

[mickeykool]

"3 - Of course the best option is to buy a cheap 2 port PCI or PCIe card.  You should never have every port in use by an array IMO"

 

Just curious why should never have every port used by array? 

 

If i have 6 ports id rather use all of it. 

[mbryanr]

OK, I guess I will order the drive and this card and make it easy on myself.

 

http://www.newegg.com/Product/Product.aspx?Item=N82E16816101358

 

 

Slightly lower price & Free shipping here

http://www.buy.com/prod/211410774.html

[BRiT]

Just curious why should never have every port used by array?   

 

If i have 6 ports id rather use all of it. 

 

I'm not sure on the logic, but maybe because it limits your recovery and preclearing options? You have no way for fast copying data or drive mirroring from the array/drive should you suspect one is faulty. You also have no means of preclearing a new drive in the system.

[mickeykool]

 

I'm not sure on the logic, but maybe because it limits your recovery and preclearing options? You have no way for fast copying data or drive mirroring from the array/drive should you suspect one is faulty. You also have no means of preclearing a new drive in the system.

 

Well that would make sense, didn't think of that. 

[SSD]

Just curious why should never have every port used by array?   

 

If i have 6 ports id rather use all of it. 

 

I'm not sure on the logic, but maybe because it limits your recovery and preclearing options? You have no way for fast copying data or drive mirroring from the array/drive should you suspect one is faulty. You also have no means of preclearing a new drive in the system.

 

Exactly.  You can fill your last port with a cache drive - as you can temporarily utilize it in an emergency.

[lionelhutz]

Well I plan on doing this in two to three weeks.  So i should stop the array, unassign the parity drive, power it off, put the new parity drive in, power it on, pre-clear it then assign it as parity right?

 

Joe, I will leave the jumper since you recommend it but why do you recommend that?  If I buy a new EARS drive what do you suggest?

 

Thanks

 

 

 

 

Yes, you could do as you posted, but it sounds like you're buying a card anyways.

 

If your EARS drive has a jumper then just leave it because it is working as good as it can get. If it is a new EARS drive then use the -A preclear option or the 4k-sector option in unRAID instead of the jumper.

 

Peter

 

 

[Joe L.]

Well I plan on doing this in two to three weeks.  So i should stop the array, unassign the parity drive, power it off, put the new parity drive in, power it on, pre-clear it then assign it as parity right?

 

Joe, I will leave the jumper since you recommend it but why do you recommend that?  If I buy a new EARS drive what do you suggest?

 

Thanks

 

 

Yes, you could do as you posted, but it sounds like you're buying a card anyways.

 

If your EARS drive has a jumper then just leave it because it is working as good as it can get. If it is a new EARS drive then use the -A preclear option or the 4k-sector option in unRAID instead of the jumper.

 

Peter

 

 

Just read the posts of those whose disk stops responding properly after they change the jumper setting.    If you've been using the disk with a jumper, great.  It is already 4k-aligned by it programatically adding 1 to each sector requested., but we don't want to also do it physically.

 

So therefore, if pre-clearing a jumpered EARS drive, use the "-a" (lower case "a") option to the preclear_disk.sh script to force it to start at sector 63.