Disk upgrade planning

[Defuse]

I am getting ready to make some hardware changes to my disk configuration and I am looking to for some tips. 

 

I currently have a 10 disk array with a single 18TB parity drive. My end state will be a 10 disk array with two 20TB parity drives. Two disks in my array are 4TB drives that I plan to also upgrade with 20TB drives.  Essentially the goal here is to get all 4 20TB drives in place without losing any data. 

 

I "think" the appropriate plan of attack is to add a single 20TB drive and assign it in the secondary parity slot. Let the array do whatever it needs to do then replace the 18TB parity drive with a 20TB parity drive, then let the array do what it needs to do to be back to a normal state. For the two data drives I presume it's safer to replace one at a time but I "think" I could replace both at this point since I now have two parity disks correct?

 

Also, for the actual hardware connections. I am also presuming that it is a good idea to separate the parity disks across controllers for redundancy. Is there a compelling reason not do this?

[itimpi]

7 hours ago, Defuse said:

I am getting ready to make some hardware changes to my disk configuration and I am looking to for some tips. 

 

I currently have a 10 disk array with a single 18TB parity drive. My end state will be a 10 disk array with two 20TB parity drives. Two disks in my array are 4TB drives that I plan to also upgrade with 20TB drives.  Essentially the goal here is to get all 4 20TB drives in place without losing any data. 

 

I "think" the appropriate plan of attack is to add a single 20TB drive and assign it in the secondary parity slot. Let the array do whatever it needs to do then replace the 18TB parity drive with a 20TB parity drive, then let the array do what it needs to do to be back to a normal state. For the two data drives I presume it's safer to replace one at a time but I "think" I could replace both at this point since I now have two parity disks correct?

 

Also, for the actual hardware connections. I am also presuming that it is a good idea to separate the parity disks across controllers for redundancy. Is there a compelling reason not do this?

All you have said looks valid although you could possibly save time by using the  Parity Swap procedure to combine upgrading a parity drive and swapping out a 4TB drive for the old parity drive.   This would leave the previous 18TB drive as a data drive instead of the 20TB you said you were going to put in place of the 4TB drive but is this an issue?  Again with dual parity two could be done at the same time but doing them separately is safer.

[Defuse]

5 hours ago, itimpi said:

All you have said looks valid although you could possibly save time by using the  Parity Swap procedure to combine upgrading a parity drive and swapping out a 4TB drive for the old parity drive.   This would leave the previous 18TB drive as a data drive instead of the 20TB you said you were going to put in place of the 4TB drive but is this an issue?  Again with dual parity two could be done at the same time but doing them separately is safer.

Ah that is a good idea as I do plan to put the current 18TB parity drive back in to the mix as a data drive. Thank you for the tip!