[PLUG] Need new solid state drives

tomas.kuchta.lists at gmail.com tomas.kuchta.lists at gmail.com
Tue Sep 22 04:55:17 UTC 2020


Disclosure - In principle, I do not think DAS is good solution to
general bulk storage - especially in Linux. I think that using NAS
would be more appropriate for bulk storage in your case - unless you
need to host multiple fast/local storage VMs on your laptop or fast SQL
DB, or similar. I understand that you do not share this opinion because
NAS cannot do 40gb/s affordably, and that is OK.

With that out of the way.

Even if you manage to get/create what you want, you will be so far from
the mainstream that it will be hard - not trouble-less life.

If I read this and your previous posts correctly - it seems to me that
your problem is not the speed of your discs or speed of the connection
to them - but the fact that your disks or disc array go to the power
saving mode or are unmounted by external usb storage timeout.

When that happens  you face nuisance with how to wake the drives/array
and then waiting for them to spin up and get mounted. Then wait a few
hours, then repeat, and ....

If my hunch is correct maybe NAS or different USB (DAS) connected
storage is the correct action to take. Something like Synology
DS218/DS220+ or similar NAS from different manufacturer could give you
115MB/s over 1Gb/s network and NFS. + you could access it from multiple
computers and manage it over decent web interface for much less $$. If
you really want to beef it up DS720+ supports 2 disks + SSD cache to
maintain fast access time over millions of small files or virtual
machine storage.

There are other manufacturers making small NAS with 10Gb/s network
interface - but that would cost and you would need 10Gb/s network card
for your laptop + network switch with at least two 10Gb/s ports -
adding $200-$300 on the top of the NAS.

The way I look at this - you boot and run you PC from fast SSD - that
is good. For normal bulk data - you typically cannot download or create
/consume data faster than over 1Gb/s anyway. So, under normal
circumstances NAS over 1Gb/s is plenty fast. That is if you do not need
to wait for spinning up sleeping discs, but that can be configured.

I cannot recommend any DAS solution, I simply do not have any good DAS
array experience with the exception of chaining SCSI external storage
disk arrays to Sun Solaris eons ago. Looking at the interwebs - there
is not many people using DAS arrays on linux either - perhaps that is a
sign of ....

Hope that you find what you are looking for.
Tomas

On Mon, 2020-09-21 at 20:50 -0700, John Jason Jordan wrote:
> On Mon, 21 Sep 2020 17:39:08 -0700
> Tomas Kuchta <tomas.kuchta.lists at gmail.com> dijo:
> 
> > My point was - Thunder bolt is maximum of 4 pcie3 lanes. It cannot
> > supply enough bandwidth to saturate more than single, not to
> > mention
> > four 4x PCIe3
> > -  striped 16GB array of NVMe is likely to cost multiple thousands
> > $$.
> > 
> > There is even less point spending 2x of that on pcie4 NVMe
> > solution.
> 
> The thing is, even if I have only 16 lanes, I'm not going to be using
> all the drives in the array at the same time. And surely there is a
> controller somewhere in the setup to shuffle I/O to the next
> available
> route. Even if I can't get the maximum that the NVMes are capable of,
> it's got to be worlds better than what I'm using now.
> 
> Setting up a 20-24TB RAID0 with NVMe drives is not easy to figure
> out.
> Apparently I'm the first one ever to do it.
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