which is the best practice? raid0 on lvm or lvm on raid0 or just one?

Hacksign · 2017-02-23 07:45:44

I have 4 disks, and this is the current layout :

Both raid1 are created with a hardware raid card.

My question is,

Q1:
which layout is the best practice if I want a best read/write performance below(regardless of the layout's boot prolem and etc.) ?

1.

| / | /var | .... |
---------------------------------------------------
| software RAID 0 |
---------------------------------------------------
| RAID 1 | RAID 1 |
--------------------------------------------------
| Disk 1 | Disk 2 | Disk 3 | Disk 4 |

2.

And some other questions :

Q2 :
How much performance lose between layout 1 and layout 3 ? (1%? 50% or more? just a quantized value to indicate that )

Q3:
Is layout 1 and layout 2 have same performance if top level filesystem is only used to store data ? I mean like this :

ratcheer · 2017-02-23 20:31:26

When I was a database administrator on UNIX systems, we always built the (hardware) RAID arrays, first, then created the logical volumes on them. We also always used RAID-10 arrays for the best performance, but you don't really have enough drives for that. It is possible to have a 4-drive RAID-10, but it doesn't really buy you anything.

Tim

Hacksign · 2017-02-24 04:08:13

ratcheer wrote:

When I was a database administrator on UNIX systems, we always built the (hardware) RAID arrays, first, then created the logical volumes on them. We also always used RAID-10 arrays for the best performance, but you don't really have enough drives for that. It is possible to have a 4-drive RAID-10, but it doesn't really buy you anything.
Tim

Why 'doesnt buy me anything ?' .
As I think a software RAID 0 will let me gain 1 time higher read/write performance on 2 raid1 disk ?

ratcheer · 2017-02-24 14:34:19

It means your stripe width would be only two drives. It buys a little performance, but not very much. I seriously doubt that it would double your performance.

The best thing would be to benchmark your throughput on your system with the drives non-striped, then repeat the exact same tests with a two-drive RAID stripe. Then you'll know what you will get, instead of just guessing.

Tim

Arch Linux

#1 2017-02-23 07:45:44

which is the best practice? raid0 on lvm or lvm on raid0 or just one?

#2 2017-02-23 20:31:26

Re: which is the best practice? raid0 on lvm or lvm on raid0 or just one?

#3 2017-02-24 04:08:13

Re: which is the best practice? raid0 on lvm or lvm on raid0 or just one?

#4 2017-02-24 14:34:19

Re: which is the best practice? raid0 on lvm or lvm on raid0 or just one?

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