4TB Logical Volume Group Query

[rjstott]

I just bought a 4TB Seagate drive and formatted it as OS X Extended Journaled as a single partition. Disk Utility now sees it as a LVG. This has limited what can be done with it i.e. it can only be partitioned into two 2TB parts, SMART info isn't available anymore. I read that this can only be resolved by using an old version of Disk Utility and an external USB setup.(prior to Fusion introduction) and there are some doubts expressed on other forums about data integrity. It is also suggested that the LVG is created because there is a SSD present in my build.

I'm curious to know whether others have seen this and whether there is any good advice? This issue seems to have been acknowledged by Apple but as no stock system except a Macpro would have a SATA 4TB it isn't perhaps a priority fix.

Anyway I fixed this using an external USB (that can address more than 2.2TB). The volume is deleted using a terminal command and then it can be reformatted using DiskUtility, This has restored things to normal and SMART is back.

 

[coelo]

This just happened to my 3TB drive.
I only want to store photos and videos on it as a backup.

Does it matter that this is a Logical Volume Group now?
It seems to work fine, but I don't want to find data corruption 2 weeks or 3 months from now. The drive is new and I can insert it in a USB enclosure as a workaround to erase it, but if a Logical Volume Group is just as good as a OS X Extended Journaled then I might just leave it as it takes hours to reformat.

Why is OS X doing this, causing drives to be turned into Logical Volume Groups?

I've never seen this before and am having a bit of trouble finding much info on it.

 

[rjstott]

I'm not sure why, but I fixed mine as I needed to create a Raid 1 Mirror, There is no evidence that the formatting will cause you a problem but because there isn't a lot of knowledge around it might be prudent to avoid this format for a backup until Apple fix the problem?

What would be good might be a lot of users chipping in with their good experience and some benefits?