True Capacity of each raid

Hi all,

I’m considering to purchase either a PR2100 or PR4100 but had a few quick questions about capacity to determine which model i’ll get.

For this example, let’s say I have a 40TB PR4100.

  1. Does the unit require any dedicated space for the OS? for. when you buy a 128gb iphone, the TRUE storage is about 124gb because 4gb is already used for the OS.

  2. Let’s say that the OS doesn’t impact the storage amount. Are the following capacities of usable storage correct:
    Raid 0: 40TB
    Raid 1: 20TB
    Raid 5: 30TB

Thanks all for your help.

  1. The OS is installed on internal flash, but the apps (Plex, logs, …) are installed on the first volume. I believe there’s a 1 GB swap and 1 GB for the OS (db, logs) per disk… (could be 500MB).

  2. You can go 4x mirror RAID1 single 10TBvolume (with hotspares) or 2x mirror RAID1 dual 10TB volume (20TB total).
    RAID0 is ridiculous, go JBOD.
    Or a single RAID5 30 TB volume (which is hard to backup though…)

I’d recommend JBOD with proper backup scripts… but it depends on the type of data.

I’m sorry for my noobiness, I’m new to raids and have learnt what I have from WD tutorials. I just checked the difference between JBOD and raid 0 and I’ll definitely be doing JBOD, but are the files stored on the one drive until it’s filled or does it spread it over the 2/4 disks in an even layout?

JBOD is just a bunch of 4 disks. You put the files where you want them.

thank you TFL for this info, i’m gonna go JBOD, just need to decide my required size :slight_smile: