I recently acquired 2 x 2x14 14 TB Seagate SAS Mach-2 drives.  I put one in my NetApp DS4246 and one directly into my server.  The dual actuator drives show up as 7TB drives and only 1 drive each.  Is there a way to get Unraid to recognize them as 14TB drive? 

Edited December 22, 20241 yr by kopuz

Last time this came I seem to remember the answer was no so this type of drive should be avoided.   I would like someone to prove me wrong.

I think disk reports the same serial number for each part but looks like two disks which is the issue.

 

Does lsblk -S show two drives with the same serial?

On 12/22/2024 at 10:39 PM, kopuz said:

SAS ... show up as 7TB drives

Correct. See the Seagate FAQ.

On 12/22/2024 at 9:39 PM, kopuz said:

I recently acquired 2 x 2x14 14 TB Seagate SAS Mach-2 drives.  I put one in my NetApp DS4246 and one directly into my server.  The dual actuator drives show up as 7TB drives and only 1 drive each.  Is there a way to get Unraid to recognize them as 14TB drive? 

What does lscsi -i show for the mach2 drives?

Working on it.  lscsi doesn't appear to be installed and NerdPack seems to be obsolete now.

I was mistaken in my original post.  I am seeing Unraid detect the drive as 2 7TB drives, so that is working as intended for the Unraid OS.  I am not sure I can return my drives just yet so I am bit curious if I was to use one of the drives as a cache pool with 2 x 7 TB.  Would that compare in performance to my Old 2x 1 TB SSDs I am using.

Edited December 24, 20241 yr by kopuz

Both found drives do have the same serial.

 

3 hours ago, kopuz said:

Both found drives do have the same serial.

 

If that is the case then I do not think that Unraid will be able to handle the drives as Unraid identifies drives by their serial number and would get confused by there being 2 drives with the same number.

5 hours ago, kopuz said:

Working on it.  lscsi doesn't appear to be installed and NerdPack seems to be obsolete now.

sorry should be lsscsi

Please post the diagnostics.
 

Interesting.  Wasn't digging through log files all day at work so was able to actually focus on the serials and they appear to be different for each of the partitions.

 

epicenter-diagnostics-20241224-2057.zip

Edited December 25, 20241 yr by kopuz

Most importantly Merry Christmas everyone!  Thanks for your time.

Edited December 25, 20241 yr by kopuz

The two halves of the disk are detected with different IDs, so no problem there, they could be used with a raidz pool for example, but both parts should be on different redundant vdevs, not sure how it would perform in the array as two disks, regarding access speed.

Has anyone had success with these Seagate EXOS "dual actuator" drives? I've got my hands on a few of the EXOS 2X14 Mach.2 - when I preclear LUN0, LUN1 goes grey and I cannot preclear LUN1 after LUN0 is successful. Does the preclear do both LUN's even though it seems to only show on one of them?