Hi all.
Current have a 3 x 8TB RaidZ1 and a 5 x 4TB RaidZ2 (these were older drives so decided to play it save.), just as well as I’m having errors on one of these drives now.
got 5 x 12TB on the way… 
plan was to round robin swop out the 4TB until the pool is build on the new 12TB’s.
question now… do I start sourcing more 12TB’s and replace, grow the second pool, or do I replace one for one the current 8TB and then use the new expand function and grow that pool with new larger drives.
G
It sounds like you have a sound plan for the RAIDZ2 pool.
The RAIDZ1 pool, well you are asking about replacing those with 12TB drives as well. Here are the things to consider:
Or are you talking about adding a 12TB drive, replace a 8TB drive, resilver, remove the 8TB drive, and repeat the process for all three drives. If this is what you desire to do, that works perfectly fine. I would only ask, is upgrading from 8TB drives to 12TB drive okay for you or would you desire 16TB drives?
I would not replace the 3x 8TB RAIDZ1 with 12TB one by one to have a 3x 12TB RAIDZ1 because (as Joe has said) this sized drive really needs to be RAIDZ2.
So, IMO, your best solution is to replace the RAIDZ2 drives one by one with 12TB until you have a 5x 12TB RAIDZ2.
You currently have 2x 8TB and 3x 4TB = 28TB useable space (with 16TB used for redundancy - a 4/11 or just over 1/3 redundancy overhead). When you have 5x12TB RAIDZ2 you will have 36TB useable in that pool, so you can then migrate your data off the 3x8TB pool.
I would then take the 3x8TB, and use 2x drives to turn it into a striped (non-redundant) HDD pool to use for temp data and / or as a backup for the critical data on the main pool.
When your main pool gets full enough to require more space, I would remove the spare 8TB drive and add a 12TB drive to add to the RAIDZ2 pool, and then when you need more space again, cease using the 2x8TB drives as a backup and add 2 more 12TB drives to the RAIDZ2 main pool.
You would end up with a single 8x 12TB RAIDZ2 pool, which is a 1/4 redundancy overhead which is significantly better than the current 4/11.
Raidz Expansion allows you to increase the width of a Raidz VDev, not the level of redundancy.
I misunderstood that. Thanks for clearing that up. Too bad it can’t change the level of redundancy. Now I’m bummed about it.
sorry guys, was on road yesterday, so saw messages come in but not able to respond while driving, ye wanted to respond with this also… and this is part of what will drive some of the to be following comments/thinking/wondering, questions in my head.
so lets start here…
Lets talk about “bunker” thats the 5 x 4TB RaidZ2 pool.
ye, the first step swop out the 4TB’s for the 12TB’s… I was away the last 7 days, got home late yesterday afternoon and the box of new drives are here… so need to move the TN to a move accessible spot and first thing is to pull the fault drive and then add in the replacement.
As it stands i don’t have immediate power point to first add the new drive in, nor a extra SAS port (did buy another LSI controller to to take me from 8x to 16x ports).
so as far as steps go, mark current problem drive offline. switch unit off. swop drives out, power back up, and then ? as new drive will have a new serial, how do i tell it to import new drive into old drive position, this process will then be followed for the other 4 drives also.
Pool “Tank” is the current 3 x 8TB.
thinking was to move those datasets onto “bunker” and then…
#option 1, destroy, get 2 more 8TB and change into a RaidZ2 build from 5 drives…
my issue with Bunker and tank is allot of space lost due to parity. thus
#option 2. instead of getting 2 more 8TB’s, rather get 2 more 12 TB’s and add then also to Bunker, and then 3 more 12TB and them to bunker… making bunker a 10 x 12Tb RaidZ2… i will sell the 3 x 8TB, or maybe change into a mirror pair for swop or something. with the 10x config i loose allot less on parity.
#3 we, instead of taking tank thats 3 x8 and adding 2 more 8TB, i add 2 x 16TB… i know i will only be able to use 8 now, but that then leads the other 3 x 8TB’s to be slowly also be replaced by 16TB resulting eventually into a 5 x 16 RaidZ2, but my comment about space lost due to parity as per above still applies.
Anyone aware of a paper, easy simple explanation of the new RaidPool extension… i heard lawrence mention they only use the added disk for parity, well that makes sense when you add one or 2 more drives… but when taking a 5 drive and extending to 10 drive… might have gap in me knowledge/education but does not make 100%. want to understand more… hope a more detailed Youtube of how this will work has been done.
G
Re this… Already mirror/push using TN Data protection RCP functionality the critical data (documents, photos, contracts) to a 2TB Google drive. to have it totally offsite. So i’m covered there… I would be crying my heart out if i lost the rest… but it will not be a “hang myself” disaster, it’s TV media, it’s Analytical LAB data etc.
G
I’m thinking of making this a 5x now… as per above, and then instead of doing anything on the 3 x 8TB simply buy more 12TB and one by one grow this to a 10x12TB.
I got a 2nd LSI controller on the way that will give me 16SAS ports total.
the onboard is 5 SAS ports, 1 of which is a M.2 drive for OS and 2 x 480GB SSD for my (Raid1) for App disk pool.
All the physical’s are then into Diskpool Bunker and Tank, As per above.
That sounds equally good.
