integrating M.2 card in raid0 system

bhelmes · 2020-09-06, 19:50

I have 6 ssd disks, combined to a raid 0 system.
Can I add a M.2 card in addition ?

I have a linux mint system and I thought of increasing speed and huge.

Greetings

Bernhard

Batalov · 2020-09-06, 20:43

Pushkin would recommend against it:

Quote:

Originally Posted by A.S.Pushkin

Anschirren Sie kein Pferd und kein zitterndes Reh auf demselben Karren

VBCurtis · 2020-09-07, 06:37

Let's see if I understand this right:

You have 6 non-M.2 SSDs. So, they're on SATA? A communications bus slow enough that any one of your SSDs is likely as fast as the bus?

So, when you stripe data across 6 SSDs on SATA, you gain almost-no speed in exchange for the loss of your entire data set if any one of the drives fails? Perhaps writes are faster, since SSD write is maybe slower than read?

Could you explain what I'm missing, since my imagined setup is daft?

kruoli · 2020-09-07, 11:37

Quote:

Originally Posted by Batalov

Anschirren Sie kein Pferd und kein zitterndes Reh auf demselben Karren.

That's really clumsy German. Did he state that in German, originally? If not, maybe: Man tut nicht gut daran, zugleich ein Pferd und ein gebrechliches Reh vor denselben Karren zu spannen.

M344587487 · 2020-09-07, 14:15

If you have M.2 slots on the motherboard use them on their own, NVMe if possible. If you have multiple M.2 slots on the motherboard you can potentially raid0 them together but it depends on the topology of the board. If you are considering a PCIe x16 card which allows for 4 M.2 drives to be plugged into it, godspeed.

TBH I don't see the point of raiding any decent NVMe drive for anything other than redundancy unless you have a very particular and expansive workload to accelerate. All that the expensive kit gets you under normal use is the smug satisfaction that your mundane read/writes are done a fraction of a second quicker.

bhelmes · 2020-09-07, 18:06

A peaceful day for you,

as far as I understand, linux regard the ssd-disk as a device and the M.2 also.
The difference in speed may be small,

the ssd-disks are pluged by the sata-bus, the M.2 card is plugged by the pci-bus,
I want to increase the huge of the whole raid0 system,
security or redundance are not important.

I have no experience with a M.2 card.

If I use a btrfs https://en.wikipedia.org/wiki/Btrfs
is it possible to connect the devices ?

Greetings

Bernhard

@Batalov : Your new logo is quite nice

chalsall · 2020-09-07, 18:51

Quote:

Originally Posted by bhelmes

I have no experience with a M.2 card.

Generally, you want all your devices in a RAID array to be the same size, and approximately the same speed.

I guess you /could/ do what you're proposing, but it doesn't seem to make sense. Some read/write requests will be really quick, others not as much. Unpredictably.

IMO, far better to build a separate RAID set, and use the filespace as appropriate for whatever work it is you're doing.

Edit: Forgot to say... I've found that a fast NVMe drive makes an ***amazing*** swap partition! I can now run jobs on my workstation that I used to have to rent cloud compute for.

M344587487 · 2020-09-08, 08:46

Quote:

Originally Posted by bhelmes

...
If I use a btrfs https://en.wikipedia.org/wiki/Btrfs
is it possible to connect the devices ?
...

If you go that route I believe ZFS is a better choice than BTRFS. ZFS stalled for a while due to licensing issues not allowing it in the Linux kernel, but now it is available everywhere and is supposedly more reliable and better supported than btrfs.

Tiered storage is a viable idea for storage but I would still have a separate M.2 as a boot device.

bhelmes · 2020-09-09, 00:56

Quote:

Originally Posted by chalsall

Generally, you want all your devices in a RAID array to be the same size, and approximately the same speed.

Generally, I want to write and read on one bigger divice in a RAID 0 array,
where the average time to write and read is better than a solid device.

I have one program which is greedy concerning ram / disk space,
but I can write datas in the background on the disk and as the datas are ordered, I can prefetch them in advance.

I try to gather some experinces with raid 0 system, and as ram is expensive
I tried to mix it with a raid 0 system. After calcalution the datas are vanished.
Therefore redundance is not needed.

Mark Rose · 2020-09-09, 01:47

Personally I'd use LVM instead of mdadm raid 0. Then you can change the underlying devices by adding and removing physical volumes from the volume group.

bhelmes · 2020-09-19, 21:45

Quote:

Originally Posted by bhelmes

I have 6 ssd disks, combined to a raid 0 system.
Can I add a M.2 card in addition ?

It is not possible.
I have an Asus motherboard 450 Plus and if a M.2 card is installed,
the bios cut the 5. and 6. ssd disks.

I will "experimentieren" a little bit with the M.2 card,
I use it now as swap partition.

Thanks for your replies.

Bernhard

2020-09-06, 19:50	#1
bhelmes Mar 2016 19×23 Posts	integrating M.2 card in raid0 system I have 6 ssd disks, combined to a raid 0 system. Can I add a M.2 card in addition ? I have a linux mint system and I thought of increasing speed and huge. Greetings Bernhard

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2020-09-07, 06:37	#3
VBCurtis "Curtis" Feb 2005 Riverside, CA 1011011011110₂ Posts	Let's see if I understand this right: You have 6 non-M.2 SSDs. So, they're on SATA? A communications bus slow enough that any one of your SSDs is likely as fast as the bus? So, when you stripe data across 6 SSDs on SATA, you gain almost-no speed in exchange for the loss of your entire data set if any one of the drives fails? Perhaps writes are faster, since SSD write is maybe slower than read? Could you explain what I'm missing, since my imagined setup is daft?

2020-09-07, 14:15	#5
M344587487 "Composite as Heck" Oct 2017 2·5²·19 Posts	If you have M.2 slots on the motherboard use them on their own, NVMe if possible. If you have multiple M.2 slots on the motherboard you can potentially raid0 them together but it depends on the topology of the board. If you are considering a PCIe x16 card which allows for 4 M.2 drives to be plugged into it, godspeed. TBH I don't see the point of raiding any decent NVMe drive for anything other than redundancy unless you have a very particular and expansive workload to accelerate. All that the expensive kit gets you under normal use is the smug satisfaction that your mundane read/writes are done a fraction of a second quicker.

2020-09-07, 18:06	#6
bhelmes Mar 2016 19·23 Posts	A peaceful day for you, as far as I understand, linux regard the ssd-disk as a device and the M.2 also. The difference in speed may be small, the ssd-disks are pluged by the sata-bus, the M.2 card is plugged by the pci-bus, I want to increase the huge of the whole raid0 system, security or redundance are not important. I have no experience with a M.2 card. If I use a btrfs https://en.wikipedia.org/wiki/Btrfs is it possible to connect the devices ? Greetings Bernhard @Batalov : Your new logo is quite nice

2020-09-09, 01:47	#10
Mark Rose "/X\(‘-‘)/X\" Jan 2013 https://pedan.tech/ 2⁴×199 Posts	Personally I'd use LVM instead of mdadm raid 0. Then you can change the underlying devices by adding and removing physical volumes from the volume group.