N4100+ RAID1

[itlity]

I have just finished the installation of RAID1 config for a N4100+ with 4 off 500GB HDDs. Result is that I have only 470GB available.

Is that normal considering that trying earlier the JBOD and RAID0 config with same HDDs, I have my expected 1.75TB available?

The N4100+ firmware is 2.0.03 and in case it matters the HDDs are of different brands.

Thanks,

Patrice

[trinode]

I guess the data is mirrored on 4 disks...

[itlity]

Is that a joke or a post of frustration? Patrice

[trinode]

IIRC the logical thing to do is to set up mirrored pairs and stripe across them. That would give you 1GB of free space and could afford you at most 2 disk failures (the wrong two fail and it's all lost).

But I'm serious it could be mirroring across all 4 drives, which would mean your data is very safe (any 3 disks can die...)

Are all the drive lights flickering when writing to the disk?

IMHO, for 4 disks RAID 5 is the way to go (you get the capacity of 3 disks (1.5 TB) and 1 drive can fail with no data loss, I've just got a second pair for my N4100+ and going from 2 disk raid 1 to 4 disk raid 5.

[itlity]

Thanks Trinode.

I got a reply from TheCus support which indicates that we cannot have 4 disks in RAID1 for the N4100+: I would have liked to see that before.

I then decided to move as you mentioned to a RAID5 configuration and it's still configuring at this very moment.

Just for my benefit and if you have that procedure/module in hand, how would you have mirrored the disks in pairs and then striped across -or was it just a suggestion?

Thanks

[trinode]

it can be done if you're happy using the command line, but not if you're using the web interface, it's not worth the risk as it could easily be broken by the web interface (which woudn't know what to do with wuch a config) or misconfigured.

I wouldn't recommend it as you only get half the space and 2 dead disks can still ruin the array, whereas you get 3 quarters of the space and still die at 2 lost disks on raid 5.

This is what I'd have hoped the device to have done (even though it doesn't say it supports 0 + 1, it does support 0 and 1 sperately...):

RAID 0+1: striped sets in a mirrored set (minimum 4 disks; even number of disks) provides fault tolerance and improved performance but increases complexity. The key difference from

RAID 1+0 is that RAID 0+1 creates a second striped set to mirror a primary striped set. The array continues to operate with one or more drives failed in the same mirror set, but if two or more drives fail on different sides of the mirroring, the data on the RAID system is lost.

[itlity]

Understood.

I'll dig again in the HEXUS forum as I think I have seen something about the support of RAID 0 + 1.

Thanks,

Patrice