Parity check / initial setup

[r1sk]

Hey,

 

I was looking around other topics related to parity check, But I wasn't able to find a decisive answer to my issues / questions.

for a new system, with a 4TB parity drive, I went and initiated a "Parity-Check" in the Main tab that is located in the WebGUI.

It is running for a while at @ 7.9 MB/sec -> which seems really slow for a lot of the numbers I am seeing around the forum, but I did noticed that other people getting this speeds for the initial parity check.

So just to make sure that this speeds are ok, other then the slow speeds I am getting a lot of error, after finishing 9% of the check I got 24,347,578 errors. is it should be like that?

 

the second thing what is the difference between parity sync and parity check, I was able to find only the parity check in the Unraid WebUI, but where is parity sync? and when should I use it if at all ? or is the both are identical and just two names for the same thing?

 

lastly , what can I do while the parity check is working? can I keep using the array ? should I stop all dockers  / plugins? read/write to the drives?

it says that the parity check will be done in -> 5 days, 9 hours, 55 minutes, should I just stop using the system until then?

 

thanks for any clarification that you can provide me!

 

---- attached system diagnostic

tower-diagnostics-20151024-2052.zip

[trurl]

It should have started a parity sync when you first started with a new parity drive. Not sure how you got to parity check before a parity sync was done. I would

 

Stop array

Unassign parity

Start array

Stop array

Assign parity

Start array

Wait for parity sync

[r1sk]

could you please explain a bit what is the difference between the two?

what does the parity sync does and what does the parity check ?

and why is it not good that the parity check is running without the sync?

[trurl]

could you please explain a bit what is the difference between the two?

what does the parity sync does and what does the parity check ?

and why is it not good that the parity check is running without the sync?

Parity sync is building parity from scratch. Parity check is checking that parity is correct. If you have never built parity, and then do a parity check, then of course you will have a lot of parity errors. Assuming you do a correcting parity check, you will get those parity errors corrected, so in the end you will have built parity. But a parity sync will build parity without bothering to check it, so it will run much faster.

[r1sk]

thanks for the info.

 

I've re-added the parity disk and now I am running the parity sync, it does seem  to work much faster now.

 

should I run a parity check right after the sync is completed ?

 

and about what can I do while I do the parity sync / check , should I stop all dockers and plugins ? or can I keep on working on the array as usual?

[itimpi]

thanks for the info.

 

I've re-added the parity disk and now I am running the parity sync, it does seem  to work much faster now.

 

should I run a parity check right after the sync is completed ?

It is a good idea to check that the parity sync built the parity correctly.  Assuming it has then you will get 0 errors reported.

 

and about what can I do while I do the parity sync / check , should I stop all dockers and plugins ? or can I keep on working on the array as usual?

There is no inherent reason to stop anything as all I/O from these do is slow down the parity sync while it is happening.  If they are very active then they may degrade the parity sync speed enough that you might decide to stop them.

 

A point to note is if you have a cache drive then it is not involved in the parity sync/check process.  Therefore if you have dockers, plugins or VMs running whose I/O is mainly to the cache drive (or a drive that is not part of the array) they should not affect the speed of the parity sync/check process.