What is Single Disk, JBOD, RAID 0, RIAD 1, RIAD 5, RIAD 6, RIAD 10?

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TMroy
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What is Single Disk, JBOD, RAID 0, RIAD 1, RIAD 5, RIAD 6, RIAD 10?

Post by TMroy » 23 Mar 2021, 14:37

What is Single Disk, JBOD, RAID 0, RIAD 1, RIAD 5, RIAD 6, RIAD 10?

In the process of using TNAS, you may need to set the array mode for your hard drives. If you are not familiar with various array modes, please refer to the following content to understand the definition and working principle of various modes.

If the following definition conflicts with the information you know, in order not to prevent you from continuing to use the TNAS device, please follow the content of this article.

1. Single Disk
Single Disk: described multiple hard disk drives operated as individual independent hard disk drives. Single Disk is an architecture using multiple hard drives exposed as individual devices. Hard drives may be treated independently.

2. JBOD
JBOD (abbreviated from "Just a Bunch Of Disks"/"Just a Bunch Of Drives") is an architecture using multiple hard drives combined into one or more logical volumes using a volume manager like LVM or mdadm, or a device-spanning filesystem like btrfs; such volumes are usually called "spanned" or "linear | SPAN | BIG". A spanned volume provides no redundancy, so failure of a single hard drive amounts to failure of the whole logical volume.
jbod11.png
JBOD is not one of the numbered RAID levels, but it is a popular method for combining multiple physical disk drives into a single logical disk. It provides no data redundancy. Drives are merely concatenated together, end to beginning, so they appear to be a single large disk. It may be referred to as SPAN or BIG (meaning just the words "span" or "big", not as acronyms).
https://en.wikipedia.org/wiki/Non-RAID_ ... tures#JBOD

3. RAID 0
RAID 0 (also known as a stripe set or striped volume) splits ("stripes") data evenly across two or more disks, without parity information, redundancy, or fault tolerance. Since RAID 0 provides no fault tolerance or redundancy, the failure of one drive will cause the entire array to fail; as a result of having data striped across all disks, the failure will result in total data loss. This configuration is typically implemented having speed as the intended goal. RAID 0 is normally used to increase performance, although it can also be used as a way to create a large logical volume out of two or more physical disks.
raid0.jpg
Normally, a RAID 0 setup can be created with disks of differing sizes, but the storage space added to the array by each disk is limited to the size of the smallest disk. For example, if a 1TB disk is striped together with a 3TB disk, the size of the array will be 1TB × 2 = 2TB. However, TerraMaster RAID implementations allow the remaining 2TB to be used for other purposes, this mean you will have total size of array 4TB.
https://en.wikipedia.org/wiki/Standard_ ... els#RAID_0

4. RAID 1
RAID 1 consists of an exact copy (or mirror) of a set of data on two or more disks; a classic RAID 1 mirrored pair contains two disks. This configuration offers no parity, striping, or spanning of disk space across multiple disks, since the data is mirrored on all disks belonging to the array, and the array can only be as big as the smallest member disk. This layout is useful when read performance or reliability is more important than write performance or the resulting data storage capacity.
raid1.jpg
The array will continue to operate so long as at least one member drive is operational.

5. RAID 10
RAID 10, also called RAID 1+0 and sometimes RAID 1&0, is similar to RAID 01 with an exception that the two used standard RAID levels are layered in the opposite order; thus, RAID 10 is a stripe of mirrors.
Raid10.jpg
Raid10.jpg (21.56 KiB) Viewed 320 times
RAID 10, as recognized by the storage industry association and as generally implemented by RAID controllers, is a RAID 0 array of mirrors, which may be two- or three-way mirrors, and requires a minimum of four drives.

According to manufacturer specifications and official independent benchmarks, in most cases RAID 10 provides better throughput and latency than all other RAID levels except RAID 0 (which wins in throughput).Thus, it is the preferable RAID level for I/O-intensive applications such as database, email, and web servers, as well as for any other use requiring high disk performance.
https://en.wikipedia.org/wiki/Nested_RA ... ls#RAID_10

6. RAID 5
RAID 5 consists of block-level striping with distributed parity. Unlike in RAID 4, parity information is distributed among the drives. It requires that all drives but one be present to operate. Upon failure of a single drive, subsequent reads can be calculated from the distributed parity such that no data is lost. RAID 5 requires at least three disks.
Raid5.jpg
Raid5.jpg (23.96 KiB) Viewed 320 times
RAID 5's distributed parity evens out the stress of a dedicated parity disk among all RAID members. Additionally, write performance is increased since all RAID members participate in the serving of write requests. Although it will not be as efficient as a striping (RAID 0) setup, because parity must still be written, this is no longer a bottleneck.

7. RAID 6
RAID 6 extends RAID 5 by adding another parity block; thus, it uses block-level striping with two parity blocks distributed across all member disks.
RAID6.png
As in RAID 5, there are many layouts of RAID 6 disk arrays depending upon the direction the data blocks are written, the location of the parity blocks with respect to the data blocks and whether or not the first data block of a subsequent stripe is written to the same drive as the last parity block of the prior stripe. The figure to the right is just one of many such layouts
To contact our tech team, please email to support(at)terra-master.com, remember to replace (at) with @

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codinghorror
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Re: What is Single Disk, JBOD, RAID 0, RIAD 1, RIAD 5, RIAD 6, RIAD 10?

Post by codinghorror » 05 Apr 2021, 11:30

One clarification about JBOD and Single Disk mode.

Can I use "Single Disk" with the F5-422 (or any multi-disk unit), so that each drive is addressible such as

[code]
/public/disk1
/public/disk2
/public/disk3
[/code]

etcetera? I would prefer to do no RAID, but I am afraid JBOD will combine all the volumes so that the failure of one disk will cause all data on the entire NAS to be lost.. is this the case? I would prefer a mode of single disk where I can read/write to each disk, and if one fails, [i]only the data on that disk is lost[/i]. Like so:

[code]
/public/disk1 ✅
/public/disk2 ❌
/public/disk3 ✅
[/code]

Is this possible? Thank you!!

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TMroy
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Re: What is Single Disk, JBOD, RAID 0, RIAD 1, RIAD 5, RIAD 6, RIAD 10?

Post by TMroy » 05 Apr 2021, 12:00

Well, "Single Disk" works independently, but it does not work as you mentioned.

As soon as you install 5 drives into your F5-422, and set all drives as "Single Disk", then you need create a volume to each drive, for example:
Drive 1/volume 1
Drive 2/volume 2
Drive 3/volume 3
Drive 4/volume 4
Drive 5/volume 5

Suppose your drive 1 is the system default drive, then the /public/ folder will only locate on your volume 1, not on others volumes. To use other space on other drives, you need to create shared folders on each volume, for example:
Drive 1/volume 1/public/
Drive 2/volume 2/tommy/
Drive 3/volume 3/shirely/
Drive 4/volume 4/david/
Drive 5/volume 5/finance/

by this way, in case one of your drives fails, all other drives will not get affected.
To contact our tech team, please email to support(at)terra-master.com, remember to replace (at) with @

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codinghorror
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Joined: 05 Apr 2021, 11:26

Re: What is Single Disk, JBOD, RAID 0, RIAD 1, RIAD 5, RIAD 6, RIAD 10?

Post by codinghorror » 07 Apr 2021, 01:16

Aha! So

1. Create a single volume on each installed hard drive
2. Create a unique shared folder for each volume on each drive

Let me try this thank you! I want JBOD but I don't want to lose ALL data if a single drive fails ;) What is the simplest possible folder format for this?

Can I have (assuming the NAS is at 192.168.1.10 for example)

\\192.168.1.10\drive-1
\\192.168.1.10\drive-2
\\192.168.1.10\drive-3

Thanks very much, I own three F5-422 and they work great! Very fast USB ingestion, copying files over at ~422MB/sec from the USB port now! Please keep improving the TOS as well ;)

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codinghorror
Posts: 9
Joined: 05 Apr 2021, 11:26

Re: What is Single Disk, JBOD, RAID 0, RIAD 1, RIAD 5, RIAD 6, RIAD 10?

Post by codinghorror » 07 Apr 2021, 03:09

OK I did it!

Created one storage pool per drive (5)

https://imgur.com/I3LklDv

Then created one volume per drive (per storage pool) (5)

https://imgur.com/cdirjFP

Then created one Shared Folder per volume (5)

https://imgur.com/KfwMpbH

Once I did that I re-opened File Manager and the five folders show up in File Manager!

https://imgur.com/ZHV7lWj

I can also access them over the network as

//192.168.1.x/disk-1
//192.168.1.x/disk-2
//192.168.1.x/disk-3

etc! Thank you for your help!! 🙌

It would be cool to add a setup mode that sets this up for you, "JBOD one folder per drive". May I humbly submit this as a feature request TMroy? This seems like a good solution for people who want maximum disk space, but also low risk (if one drive fails, only the data on that particular drive is lost).

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