[OmniOS-discuss] Debating Swapping 2TB with 4TB drives in RaidZ2 or Create new Vol and clone

[Matthew Mabis]

I know the drive itself does 512b emulation but i would rather run 4K if theres a performance increase!

thanks

Matt 





----- Original Message -----
From: "Chris Siebenmann" <cks at cs.toronto.edu>
To: "Matthew Mabis" <mmabis at vmware.com>
Cc: omnios-discuss at lists.omniti.com
Sent: Friday, March 21, 2014 9:04:37 AM
Subject: Re: [OmniOS-discuss] Debating Swapping 2TB with 4TB drives in RaidZ2 or Create new Vol and clone

| I am debating the idea of just swapping all my hard drives in my
| current 8x2TB RaidZ2 (all be it slowly) and let the environment
| resilver each drive than expand versus creating a new RaidZ2 on a
| different box and cloning the data over.
|
| Obviously i know of the Pros/Cons/Risks associated with that
| method. My question about debating deals with the new drives being 4K
| where as the old drives were 512b aligned [...]

 As far as I know there is no question here: you simply cannot put 4K
drives in a vdev originally created with 512b drives[*]. You need to
make a new pool with the 4K drives.

 Even if you could get them into the existing pool, the performance
effects would likely be relatively bad. ZFS does a lot of unaligned
writes.

	- cks
[*: If we're being technical, it's possible to force OmniOS to think
    that they're all 512b drives.
]