Many Thanks @johnnie.black

 

I will try 2 MX500's (I already have 1) so will order another.  although my mainboard has 3 nvme slots so that may be another way to go, I have 1 or 2 Samsung evo's lying around and 1 on my main rig.

 

If 4 fast SSD's won't give more than 500 how to you get 700? is it because of the quantity? what raid version are you using?

 

Thanks

Edited April 4, 20197 yr by mbc0

I am looking at 2 Intel 660p Series M.2 Drives

 

My theory is that I could use 2 of these in RAID 1 Mirror, I should get around 700/900mb/s using this config?

 

General

Device TypeSolid state drive - internal

Capacity1 TB

Hardware EncryptionYes

Encryption Algorithm256-bit AES

NAND Flash Memory Type3D quad-level cell (QLC)

Form FactorM.2 2280

InterfacePCI Express 3.0 x4 (NVMe)

FeaturesSmart Response Technology, End-to-end data protection, Rapid Start Technology

Width22 mm

Depth80 mm

Weight10 g

Performance

SSD Endurance200 TB

Internal Data Rate1800 MBps (read) / 1800 MBps (write)

4KB Random Read150000 IOPS

4KB Random Write220000 IOPS

Intel 660p are QLC, IIRC sustained write speed after the pseudo SLC cache is full goes down to 100MB/s.

Ok,

 

so I need to find a NVME drive that does not use QLC like the Kingston which uses a 3D NAND Technology, NVM Express (NVMe), Phison E8 controller

 

Can you confirm that if I use two in mirror mode I can expect roughly half of the performance?

 

Looking at 2 X 1TB capable of 1800mb/s would it be unreasonable to expect 700-800mb/s in Raid 1 Mirror mode?

 

Thanks

27 minutes ago, mbc0 said:

the Kingston which uses a 3D NAND Technology, NVM Express (NVMe), Phison E8 controller

I'm guessing you mean the A1000, no personal experience with these, but quick search shows they might not be that fast:

Also look at the 660p performance when full (with no or little SLC cache left):

IMO if you want performance you should go with the Samsung EVO, they are a little more expensive, but you seldom can get cheap and fast, I have two 1TB 970 EVOs on my desktop and am very happy with then, now would be the 970 EVO Plus.

Ok, that is great information, many thanks!

 

I have a 960 Evo in my Desktop as the OS disk and like you cannot complain

 

Can you confirm that if I use two in mirror mode I can expect roughly half of the performance?

 

Looking at 2 X 1TB capable of 1800mb/s would it be unreasonable to expect 700-800mb/s in Raid 1 Mirror mode?

11 minutes ago, mbc0 said:

Can you confirm that if I use two in mirror mode I can expect roughly half of the performance?

In mirror you should get about the same performance as a single device, though in my experience you'll never get quoted (or even benchmarked) performance in real world use.

 

12 minutes ago, mbc0 said:

Looking at 2 X 1TB capable of 1800mb/s would it be unreasonable to expect 700-800mb/s in Raid 1 Mirror mode?

700/800MB/s is about what I would expect with a fast device, like the 970 EVO, with single device or mirror.

That's great, as always thanks for the advice, I will let you know how I get on 🙂

Hi @johnnie.black

 

Just following up my issue.

I have replaced the 4 X 500GB SSD Cache Pool with 1TB Samsung NVME 970 Evo Plus and can now transfer at 950MB/s to 1000MB/S when copying from NVME on my Desktop to unRAID without any glitches or slowdowns so VERY happy with this 🙂

👍

 

On 4/2/2019 at 7:56 AM, johnnie.black said:

On 4/2/2019 at 7:47 AM, mbc0 said:

Is there a "Safer" way to run a SSD pool? 

Make sure all shares are set to COW.

 

Any problem converting the system share containing the docker and libvirt images to COW?

21 minutes ago, aim60 said:

Any problem converting the system share containing the docker and libvirt images to COW?

No, but only new files written to that share, or re-written, will have checksums.