[CALUG] Recommendations for NAS with Solid State Drives

Open Source Rocks opn.src.rocks at gmail.com
Tue Aug 3 08:20:26 EDT 2021

Totally agree with Bryan - I have Synology DS-1621+ - it does have 2 M.2
for cache acceleration. They do provide brackets to install solid state
drives into the NAS, similar to others.
I replaced my dead Drobo from a few months back with this model - have
loved it since. Though the only annoying part thus far is the very
expensive ECC memory upgrade. (comes with 4 GB RAM, can be upgraded to 16

Interface/UI is very easy and there are a lot of apps to make your life
easier. They do have a capability to connect to the internet, however, I
have not enabled it or plan to do so.

I have 6 "rust disks" ;) and have not gotten a hit on performance, YET - I
am running a docker/minecraft server for the kids and his friends (max of 6
kids), a docker/Calibre-Web (2 users), Plex Server for my music, photos
uploads from phone, folder sharing between 5 people and a print server for
the house.


On Mon, Aug 2, 2021 at 11:28 PM Bryan Smith <me at bjsmith.me> wrote:

> On Mon, Aug 2, 2021 at 10:33 PM Thomas Delrue <thomas at epistulae.net>
> wrote:
>> Does anyone have experience and/or recommendations for a good NAS with
>> Solid State drives? Has anyone done this or am I crazy for even wanting
>> to do this?
> Almost all NAS (and SAN) solutions over the last five-plus (5+) years are
> either two (2) types ...
>  - Hybrid NAND cache and optional buffer + platter-backed (i.e., platter
> is the permanent store), and ...
>  - NAND-only (no platter)
> This is definitely so as NAND not only overtook 2.5" in density, but can
> far fit more in 2.5" than 3.5" platter can.
> E.g., Samsung PM1643 can fit 30TB in 2.5" x 15mm, and 10-20TB in 7-10mm
> high, and still use no more than 12W (12V at 1A), and often under 5W.
> There are variants on the Hybrid NAND solution, especially since NAND
> cells *'wear out' *on writes much faster than magnetic platter, and have
> a much higher error rate (although such is compensated by firmware).
> But pure NAND NAS/SAN are now becoming very common.
> E.g., I just spec'd out an IBM SVC 2.5" shelf with 0.7PB (0.5PB) usable in
> a 2U chassis.
> It's only a matter of cost (30TB is about $5K).
> Are there folks running a QNAP device with a properly RAIDed solid state
>> drive-based array? What are the things to keep in mind, do or
>> specifically not do?
> Before that, consider the fact that there are several types of NAND
> interfaces.  I'll start with the one you know.
> AHCI/SATA - This is the legacy SATA physical connection, legacy host
> controller interface -- compatible going back to the old IBM PC/Seagate
> ST506 commanding
> SATA, in the 3rd iteration (aka SATA3), as you already know, is ~6Gbps
> (~0.6GBps at typical 10:8 encoding).
> There is also SAS (Serial Attached SCSI-3), which in quad-channel (SAS
> uses more conservative signaling), is ~12GBps (~1.2GBpsat typical 10:8
> encoding), aka SAS 12Gbps.
> AHCI/PCIe - This is the new PCIe x1-4 channel physical connection, but
> still with the legacy interface for full OS/legacy boot compatibility
> (ST506).
> nVME/PCIe - This is the new PCIe x1-4 channel physical connection, and
> with the new, far more parallel interface, but it is not legacy compatible
> (e.g., need new firmware/OS for boot)
> PCIe 3.0 in a single x1 lane is capable of 10Gbps (~1GBps at typical 10:8
> encoding), which is another 2/3rds as fast as SATA in throughput, so x2 is
> over 3x faster, x4 is over 6x faster.
> nVME can also command far more efficiently, and to far more I/O operations
> than legacy ST506 compatible AHCI that is traditionally used.
> When it comes to actual, physical interfaces, there are several now that
> exist beyond SATA.
> M.2 slot (22mm/0.9" wide, 20-80mm/0.8-3.2" long) - Depending on the keying
> type, whether B, M or other, there are SATA and/or PCIe x2 or x4 lanes
> U.2 connector (cable) - This is the 'cabled' variant of M.2, actually
> based on 'SATA Express' (SATA/SAS-connector based, but SATA + PCIe x2), but
> only provides PCIe x4 lanes (no SATA)
> So ...
> What you're looking for is to find a NAS that can maximize the benefits of
> NAND devices, especially with M.2 nVME/PCIe x4 (or U.2 nVM/PCIe x4 when it
> comes to lots of drives/bays).
> I assume this is just for a SOHO system with maybe 5-6 drives max in
> RAID-6, to give the equivalent 'usable' 3-4 capacity.
> E.g., (6) 1TB drives in RAID-6 = 4TB usable (equivalent of 4 drives usable)
> Now that assumes pure NAND.
> If you're looking for hybrid, there are various options ... including NAS
> devices that can provide 1-2 M.2 nVME/PCIe x4 slots.
> There are others than only have 2.5" bays.
> E.g., I have a tiny little (2.5" based) Synology DS620 (no nVME/PCIe, only
> AHCI/SATA) and I've populated it as follows ...
> (4) 5TB 2.5"x15mm SATA platters in RAID-5 for 15TB usable
> (2) 0.5TB 2.5"x7mm SATA NAND for cache+buffer (read+write) in RAID-1
> (write failover)
> Synology requires two (2) NAND devices for buffer (write), otherwise just
> using one (1) NAND device, will only enable cache (read-only).
> E.g., I could have done ...
> (5) 5TB 2.5"x15mm SATA platters in RAID-5 for 20TB usable
> (1) 0.5TB 2.5"x7mm SATA NAND for cache-only (read-only)
> - In terms of how to access the data: NFS is the only real requirement,
>> no samba, or whatever. But scp would be nice too...
>> Like I said: I'm fine sticking with QNAP. I just don't know if I'm crazy
>> for wanting to stuff it with solid state drives (would NVMe be doable?)
>> instead of spinning rust ones...or whether this is doable at all.
>> Are there other considerations that I should take into account?
> The biggest problem I have with most SOHO NAS devices is they suck for
> NFS, and aren't really NFSv4 feature complete.  I use them more for iSCSI
> block (as well as as a media server) but that's another story.
>> Are there other vendors that I should look at that specifically offer a
>> device like this?
> I'd be interested in finding a capable SOHO NAS vendor that offered IPA +
> NFSv4 out-of-the-box so I can *'drop in'* a low-power ARMv8 or BGA
> (embedded) x86-64 with POSIX (UNIX/Linux) Identity + File in one system.
> But most vendors are targeting the 98% of SOHO customers that run Windows.
> - bjs
> --
> Bryan J Smith  -  http://www.linkedin.com/in/bjsmith
> E-mail:  b.j.smith at ieee.org  or  me at bjsmith.me
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