New Build, 2nd Parity Check taking same time as first?

[jeffreywhunter]

My first parity check just finished.  Read on a post that the second parity check should take less time, but its taking as long as the first parity check.  Is that correct?

[trurl]

My first parity check just finished.  Read on a post that the second parity check should take less time, but its taking as long as the first parity check.  Is that correct?

Don't know any reason a parity check should be expected to be any faster or slower unless something is not working quite right. Perhaps you were reading about a parity sync (build).

[jeffreywhunter]

Yeah, sorry, i should have retained the post.  Can't find it now.  As long as it takes what it takes, then I'm good.  With all the troubles I've had getting hardware to work, was just concerned something was amiss because of what I had heard from others...

 

Back to the grind!

[garycase]

Barring a chance in your configuration, all of your parity checks should take essentially the same amount of time.

 

The only exception would be if the system was having issues that caused multiple read attempts on some of the drives; or if there were a lot of sync errors that had to be corrected ... and even this would normally not add a LOT of additional time to the process.

 

[pkn]

According to my latest observations  , parity check, which typically goes after initial parity sync, actually takes longer.

 

Because in  parity sync there is only one active process mdrecoveryd, and in parity check there are two: mdrecoveryd and unraidd.

[jeffreywhunter]

So the practice should be, until you have built directory structures, loaded up initial files, etc.  Just skip the parity check.  Esp when boot/reboot is in process...

[garycase]

So the practice should be, until you have built directory structures, loaded up initial files, etc.  Just skip the parity check.  Esp when boot/reboot is in process...

 

If you mean skip the assignment of a parity drive, I don't recommend it;  although some do like to do the initial load of their data before they assign parity because of the much higher write speeds.

 

A parity CHECK  has nothing to do with an initial parity SYNC -- which is the initial process that builds parity on the parity drive after you've assigned it.

 

A parity check has nothing to do with building directory structures, loading initial data, etc.

 

Once you have a fault-tolerant array (i.e. with a parity drive), writes are much slower than without a parity drive, since every write requires 4 disk operations.