Hi Everyone, a quick question which I did not find searching.

Can I clean shutdown my Towers, change the SAS controllers, power up and be on my way? BUT - I really need to do a Parity check as I have added a lot of data.

 

1- Should I do a Parity check first, then change the controllers?

2- Or go ahead and change the controllers then do the parity check?

 

Am running 6.5.3 in both my towers, they are Marval based controllers. currently installed.

Tower1 is running 2x Parity and 10x 8Tb drives.

Tower2 is running 2x Parity and 20x 2Tb drives.
Just received 4x LSI SAS 9207-8i today, which I am looking forward to installing.

 

Appreciate your advice and experience as always.

Cheers

Steve

In theory parity should be fine as in Unraid parity is real-time.    However doing a periodic check is a good idea.

 

Personally I would change the controller first as the Marvell controllers are more likely to drop a disk.   In theory it should be a case of simply swapping in the new controller, plugging the drives to it and rebooting the system to be back where you were but using the new controllers. You could then run the parity check which would also check the new controllers are working as expected.    However doing the parity check first is definitely an option if you would rather get that out of the way before disturbing any hardware.

I would do a Screenshot of the disk assignments prior to starting the conversion.  You should not need them but having it in hand will virtually guarantee that you will not need them (One of Mr Murphy's Laws...). 

Thanks to you both, Much appreciated.

 

I do have a screenshot of disk assignments, anytime I add a disk, I take a screenshot and print it.

Sticky tape it inside the side cover. I also use a labelling machine for the last 4 digits of serial number. Easy to know which disk is which.

 

Think I will do a parity tonight, before I disturb anything, then do the changes.

 

Thanks for the confirmation that either way works.

 

 

27 minutes ago, HK-Steve said:

 I really need to do a Parity check as I have added a lot of data.

The way you worded that makes me think you have a misconception of parity. How full the drives are has no bearing on the parity calculation. All drives participate fully in parity, regardless of content. A completely empty drive still has all of its bits calculated by parity,  all the way to the end, even if the bits have no files defined.

 

That's why all drives must be completely healthy to rebuild a failed drive, even empty drives must be read perfectly.

Thanks jonathanm, 

I understand how parity works, that is why I have used UnRaid for over 10 years+ now. I am just not an expert user as many of You are. Thanks.

Was concerned that after adding about 5Tb total to 6 or 7 disks, that I should do a Parity check now before making hardware changes, or after for a more reliable controller.

I have started a parity check on both Towers now.

 

Thanks again. Much appreciated as always.