Running out of space, hard drive upgrade options.

MHELO

Cadet
Joined
Dec 9, 2017
Messages
8
Hello, I've been running FreeNAS/TrueNas for a little over 3 years now and I've really enjoyed it so far but it's time to upgrade the hard drives because I'm running out of space. Currently I have 4x 3TB hard drives as part of one pool called "media". I wanted to confirm I understood the "Extending a Storage Pool" documentation (https://www.truenas.com/docs/hub/tasks/advanced/extendpool/). Based on the zpool status output below, it shows I have 2 different mirrors. If I wanted to add another 2x hard drives would they have to be 3TB as well? The documentation says "Mixing disks of different sizes in a vdev is not allowed" but I wanted to confirm what this meant. I have 2x new 8TB hard drives which I was hoping to just add as another mirrored pair and extend the same pool but I've read this is not advisable because the performance would not be optimal. I'm also curious what are the benefits of performing the "zpool upgrade" is. Any input and/or suggestions would be appreciated. Thank you.

Output of "zpool status":
Code:
  pool: media
 state: ONLINE
status: Some supported features are not enabled on the pool. The pool can
        still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
        the pool may no longer be accessible by software that does not support
        the features. See zpool-features(5) for details.
  scan: scrub repaired 0B in 05:03:16 with 0 errors on Sun Feb  7 05:03:16 2021
config:

        NAME                                            STATE     READ WRITE CKSUM
        media                                           ONLINE       0     0     0
          mirror-0                                      ONLINE       0     0     0
            gptid/4836a31c-03a8-11e8-9485-ac1f6b251696  ONLINE       0     0     0
            gptid/48eb5f41-03a8-11e8-9485-ac1f6b251696  ONLINE       0     0     0
          mirror-1                                      ONLINE       0     0     0
            gptid/49a00d98-03a8-11e8-9485-ac1f6b251696  ONLINE       0     0     0
            gptid/4a4ed7c8-03a8-11e8-9485-ac1f6b251696  ONLINE       0     0     0

errors: No known data errors
 

ChrisRJ

Wizard
Joined
Oct 23, 2020
Messages
1,903
media is your pool, while mirror-0 and mirror-1 are its underlying vdevs. So it is a perfectly valid approach to create a third mirror (mirror-2) out of your two 8 TB drives and extend media with it.

As to zpool upgrade I usually ignore this, but that is more out of general "paranoia" than for a particular reason.
 
Last edited:

MHELO

Cadet
Joined
Dec 9, 2017
Messages
8
media is your pool, while mirror-0 and mirror-1 are its underlying vdevs. So it is a perfectly valid approach to create a third mirror (mirror-2) out of your two 8 TB drives and extend media with it.

As to zpool upgrade I usually ignore this, but that is more out of general "paranoia" than for a particular reason.
Thank you. I figured I was on the right track. To confirm, there shouldn't be any performance issues due to the fact of the drives being different sizes? I read somewhere that it will tend to fill the drives with less space first but I don't know if that is true or not.
 

Etorix

Wizard
Joined
Dec 30, 2020
Messages
2,107
Your existing vdevs being full, most writes will be directed to the new vdev, which means that, for the new data, your pool will essentially have the performance of this single vdev.

An alternative option would be to replace both drives in one of your vdevs with the 8 TB drives (and probably buy two further drives to replace the second vdev). Stripes with vdevs of different sizes are perfectly fine.

Sanity check: Are the 8 TB drives of a safe CMR type?
 

MHELO

Cadet
Joined
Dec 9, 2017
Messages
8
Your existing vdevs being full, most writes will be directed to the new vdev, which means that, for the new data, your pool will essentially have the performance of this single vdev.

An alternative option would be to replace both drives in one of your vdevs with the 8 TB drives (and probably buy two further drives to replace the second vdev). Stripes with vdevs of different sizes are perfectly fine.

Sanity check: Are the 8 TB drives of a safe CMR type?
I didn't realize checking the CMR if it was a safe type was something to consider.

Existing (Old) Drives: 4x 3TB WD Red WD30EFRX
New Drives: 2x 8TB WD Red Plus WD80EFAX

From what I read (https://www.ixsystems.com/blog/wd-red-plus-drives/) I believe the old drives are safe since they don't have "EFAX" in the model number and the new drives are safe because they are branded as "Red Plus". Please confirm if I misunderstood. Thank you for the sanity check.
 

Dirk

Patron
Joined
May 23, 2016
Messages
206
I didn't realize checking the CMR if it was a safe type was something to consider.

Existing (Old) Drives: 4x 3TB WD Red WD30EFRX
New Drives: 2x 8TB WD Red Plus WD80EFAX

From what I read (https://www.ixsystems.com/blog/wd-red-plus-drives/) I believe the old drives are safe since they don't have "EFAX" in the model number and the new drives are safe because they are branded as "Red Plus". Please confirm if I misunderstood. Thank you for the sanity check.

I know I'm late on this but saw your last message didn't get a response and I recently went around the block with WD on 5 drives I purchased and they agreed to replace with the CMR drives. I then received 5 recon drives and went around the block again. You are correct on your research of CMR SMR
We found the SMR drives were in the 2TB to 6TB lot and some 2TB originally shipped as CMR. Anything outside was CMR. Go with the EFRX. I just lost one of six 2TB CMR drives that have all been 24/7 for six years..
 
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