BTRFS vs EXT4

[BurnsyD17]

Hello.
I've setup my new F4-210 with 4x Ironwolf 4TB drives.
When prompted to create a Storage Pool, I chose RAID5. I plan to use the entire NAS as a single big storage space where my Windows PC can create content and store it there, and then a separate standalone Ubunutu-based Plex server will share the content on my LAN.
I was given a choice when creating the Volume to use either btrfs or ext4 and I am not sure which would be best for my situation. Seeming as it's more "advanced", I chose btrfs, however the Synchronizing process that is underway says the capacity of the volume will be only 10.9TB. Under RAID5 I expected to see something more like 12TB (the capacity of 3 of the 4 drives due to RAID5 parity). Am I seeing only 10.9TB because I chose btrfs, would I have seen more capacity if I chose ext4 instead? I am still early enough in the process where it is no big deal to switch if I would end up with more usable capacity.



Thanks for the help!

[TMS]

Hi,
For hard disk capacity, please refer to this link: https://support.terra-master.com/faqs/t ... _displayed

[BurnsyD17]

Yes, I am quite familiar with the difference between "marketed" capacity versus "displayed" capacity wrt disk drives, but that wasn't really the question.

Will there be a difference in "usable" capacity between using btrfs versus ext4, on my F4-210? Considering that almost all the data stored on the NAS will be media files on the order of 4-20 GB each?

Also, I've read FAQ's and articles and such on btrfs versus ext4, but it isn't clear how or if any of the more advanced features of btrfs would benefit this use case, as implemented in TOS?

Thanks

[TMzethar]

The ext4 format will retain about 1~5% of reserved partitions, so the capacity will be a little smaller than btrfs. Btrfs has a snapshot function and a shared folder quota function that ext4 does not have. ext4 will be more stable in terms of stability.

[BurnsyD17]

Thanks for the explain. You might want to include this information in a future TOS update on the screen where the option is presented. Just a thought.

[djonesuk]

Hi, new F5-221 owner here

Firstly, I can confirm that 3 x 4TB drives have a capacity of 10.9 TiB. This is because 1 "Storage TB" = 1 x 10^12 bytes whereas 1 TB = 1 x 2^40 bytes.

On the synchronisation issue, this isn't actually down to BTRFS. When you create a RAID5 volume, the volume manager has to synchronise the parity blocks. It doesn't matter what file system you use this will be the case. You can read more about it here.

hope that helps!