how to replace parity drive without loosing protection?

[MoherPower]

Hi

 

I am trying to replace my 2x6TB prity drives to new 2x8TB. but all procedures i found require to degrade arry by pulling 1 or even 2 drives and than rebuilding. I have 2 free slots left in server just for case like this. I could add NEW unasigned drive and COPPY parity information from one 6tb to 8tb drive. and THAN remove copied parity so while this process is done i am alvays protected. Is there a possibility to do this in safe way? 

[Vr2Io]

Start array in maintenance mode then rebuild parity, if any fault happen, you can put back the original disk. Even not rebuild in maintenance mode, array still protect by other parity disk.

The first step, should be check parity to ensure no error and well sync.

 

 

[MoherPower]

The problem in all of those scenarios is this. Unraid server works in company and is used as backup storage for all pc(64) / servers(4).  Puting array off for 24h is not acceptable  and more over when parity will be rebuild on new disk there will be writes form backup to array too, so my old parity disk will be not valid if anything goes wrong. Is there no other way to copy data from one parity to another without braking parity for a period of time??

[Vr2Io]

Any written during live rebuild is ok , new and old parity disk will update ( of course not replaced disk ), but array read/write performance also seriously impact, almost unuseable.

 

Copy parity wont have benfit

Edited May 16, 2022 by Vr2Io

[Zonediver]

24 minutes ago, MoherPower said:

Puting array off for 24h is not acceptable

 

...then you need a second (synced) unraid-server...

[Vr2Io]

Or use parity rebuild schedule plugin, only rebuild several hours in night time until fully rebuild

[MoherPower]

34 minutes ago, Vr2Io said:

Any written during live rebuild is ok , new and old parity disk will update ( of course not replaced disk ), but array read/write performance also seriously impact, almost unuseable.

 

Copy parity wont have benfit

how old parity disk will update if this disk is supposed to be taken out from unraid? the procedure is as far as i know 

1) stop array and take out first parity disk

2) start array and stop after information about parity disk missing

3) assign new parity (precleared/checked) and rebuild parity.

 

so how old parity drive will update since this disk will lay on my desk?. 

 

Can i just stop array and assign new parity disk without removing old one from server so the information will be coppied from old to new? 

[Vr2Io]

You said array/data always update, so I don't understand the purpose of copy parity disk.

 

Unraid can't remember the change and update the change in later.

Edited May 16, 2022 by Vr2Io

[Vr2Io]

8 minutes ago, MoherPower said:

so how old parity drive will update since this disk will lay on my desk?. 

 

50 minutes ago, Vr2Io said:

( of course not replaced disk )

 

[Michael_P]

Just do one at a time if uptime is your primary goal, "protection" would be just limited to 1 disk failure

[Frank1940]

14 hours ago, MoherPower said:

I am trying to replace my 2x6TB prity drives to new 2x8TB. but all procedures i found require to degrade arry by pulling 1 or even 2 drives and than rebuilding. I have 2 free slots left in server just for case like this. I could add NEW unasigned drive and COPPY parity information from one 6tb to 8tb drive. and THAN remove copied parity so while this process is done i am alvays protected. Is there a possibility to do this in safe way? 

 

Before you even start, why are you only going from 6TB to 8TB size parity if uptime is a major factor.  (You obviously need much additional storage as you have two spare slots where you could install one or two additional 6TB data data drives.)  I would suggest that you look at drives not smaller than 10TB and even consider 16TB drives.  (I would be looking at how fast my database needs are growing and size the parity drives so that I would be facing this task again for five years minimum.)  

 

Have a good at the Parity Check Tuning plugin as it provides for many useful features for those with large-size parity drives.  (I hope you have Notifications setup and are running monthly parity checks since this is apparently a business server.  You want to be made aware of any and all problems before they become apparent in actual server operation...)

 

As @Michael_P suggested, you can just replace one parity drive at a time and still have one disk failure recovery until the parity rebuild is completed on the replaced parity disk.   To decrease the odds of having a problem during a rebuild, run a non-correcting parity to verify you don't have any problem before you do the first  replacement.  (Obviously, if there were to be a problem, you would need to address that first!)

[vamitrou]

Resurrecting this old thread since I am also interesting to upgrade parity. 

 

In theory, if one writes all 0s to the new drive, and then dd the old parity to the new parity, will this make the new disk ready and up to date?