Taking extra precaution before upgrading HDDs (parity & data drive)

[unP]

Hi!

I wanted to consult my situation before performing the upgrade. My aim is to upgrade both parity and one data drive - upgrading my 6TBs to 12TBs. I`m scared of data loss or any other crap that might happen during the upgrade and honestly, I`m not confident with just replacing the parity drive, let it sync and then do the same with data drive (because my server uses just 1 parity drive). 

Therefore, all I wanted to consult is this procedure:

- upgrade/update everything in the server so it runs the latest SW

- disable all planned activities (mover, parity checks, backups)

- disable autostart of the array & docker/VMs

- perform flash backup

- start array in maintance mode & let it sync the parity

- unmount SSD cache disk (assigned in cache pool) and pull out completely

- mount the new 12TB drive instead of cache and make it 2nd parity drive

- let the new parity drive sync

- pull out old data drive & put in new 12TB new one

- let the server rebuild the data drive

- pull out 1st old parity drive (6TB one)

- put in cache drive to the original slot

- rewind all the changed settings

- live happily ever after

 

Summary:

- old state: 1 parity (6TB) + 4 x data (6TB) + 1 SSD cache

- new state: 1 parity (12Tb) + 3 x data (6tb) + 1 x data (12TB) + 1 SSD cache)

 

Is this procedure safe & and actually doable? Have I forgotten anything which should be definitely done?

 

PS: My MB offers 6 SATA ports, all of which are used. I wouldn`t be asking if I had large server with all the SATA slots I needed.

 

Thx a lot for the response! (I`m getting gray hair and haven`t even started  )

[JonathanM]

Unfortunately your procedure won't work unless you get ANOTHER 12TB drive. No data drive can be larger than either parity drive, so until both parity1 and parity2 are 12TB, you can't install a 12TB data drive.

 

The parity drive holds zero data, it only works in conjunction with all the other data drives, so as long as all your data drives are healthy, and a very recent parity check had zero errors, swapping the parity for a larger one is a infinitesimally small risk. It's pretty much a zero risk if you do it in maintenance mode, since if a data drive died while you were upgrading parity you could just put the old parity back in.

 

Also, since you are scared of data loss, I take it you have no backups? Parity isn't a backup, its only purpose is to allow a single dead drive to be rebuilt. Deletion or corruption of your data, from any source, isn't recoverable with parity, you must have backups.

 

I think before you start upgrading your server, you need to get your data backed up so that if something does go wrong it's not catastrophic for you.

[unP]

Hi @JonathanM,

 

thx for such a brisk answer. I wasn`t sure about the parity drive logic so kudos to your comment. I don`t have other 12TBs on me at the moment so can`t perform the action I pointed out above....now it`s clear to me. 

I do have backups but it`d take ages to restore them....that`s why I was asking  

 

Btw all data drives returned SMART extended status as OK and parity check ended tonight with 0 errors...since then I haven`t started the array in normal mode, only maintance. 

 

Therefore, I`ll start the upgrade process as per your comment. In case everything goes fine, I won`t bother you any further 🙂