Synology 918+ M.2 SSD suggestion

Hi, as my actual NAS is now 95% full… i’m going to buy a new NAS, synology 918+, and expand considerably my storage space.
i’d like to have some suggestions about which M.2 SSD to buy as cache. i mean, the NAS has 2 slots…
but i don’t really know the function of these M.2 cache, do 2x256 Giga of ram have a meaning? are the standard 8Gb Ram not sufficient?

The m.2 cache slots on synology units can’t be used as storage at this time. So it’s only to improve access to often used files and improve read write times for large files. You probably don’t need them…and can’t use them as a roon server database location either. Qnap nas I think you can however.

Hello Niccolo,

I am facing the same thing. My Synology 415+ is pretty much full.
I am thinking about purchasing the 918+.

About the M.2 slots. I don’t think this is memory, but merely a unique opportunity to stream the music effortless to your streaming device.
Compare it for instance to an Aurender N100H which also has a small portion ssd on board which holds the Aurender operating system ( Roon Core ) and helps to buffer the stream.

The beauty about replacing a Synology for a Synology is, that you can replace all four disks into the new unit, should you wish to do so. All the data and raid system are retained.

In the meantime me myself, i am wondering whether i can transfer the M.2 card with roon rock on it, straight into the Synology 918+. Anyone ?

Synology m.2 is cache only use, rock would be overwritten and rock does not run on synology hardware anyway.

Going from one 4 bay nas to another using the same drives only maybe improves the nas performance, you won’t gain more space unless you expand to another chassis with more slots or add an expansion bay. Or add new bigger drives and migrate the data over to the new volumes.

Use the old nas a s a backup is a good plan, and get new nas with new bigger drives

Honestly, none. Put the money towards expanding the RAM to max on the system, instead.

Synology currently uses flashcache under the hood (though the release notes for the DSM 7 alpha suggest they may finally be changing this). flashcache is ANCIENT and basically abandoned by the Linux mainstream. It has SEVERE write amplification issues, meaning it burns through SSDs at an accelerated rate. It will chew through the write endurance of consumer-grade SSDs (like Samsung EVOs) in as little as a year. And for most home-NAS workloads, provides very little actual speed benefit. Whereas maxing out the RAM has a real performance benefit. (It’s not about how much memory the apps on the NAS have allocated — it’s about Linux using “unallocated” RAM as block I/O cache.)


I dont understand this SSD cache thing :smiley: the weakpoint is the 1 GBit connection which maxes out at 113 MB/s. When copying things inside my NAS from one dir to another its about 300 MB/s (RAID5) and my SSD inside my computer is not much faster. So I cant see how a SSD cache could improve things. Buy more RAM for your NAS or bigger HDDs :smiley:

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ok, thanks everybody. no m.2 ssd. except that next upgrade of synology will allow to use them for installing software (roon) instead of usind an external USB SSD.

yes, i’m going from a 2 bay synology to this, and definitively buying much bigger HD.

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well you never indicated what your current NAS was. Helps when we have the big picture. So what is your current model?

My actual NAS is a DS213, with 2 4TB HDs. now at 98%.

I had previously a QNAP, but with not so good experience.
So, even though i was considering also e 4bay QNAP, at the end i decided to pass to the synology DS918+, basically for 2 reasons:
-intel, i’ll try to install roon core directly there. people have done that, and are satisfied. it should work for me, as i don’t do DSP, and have basically at most 2 zones.
-it can be expanded. i don’t know if that has any sense, but i want that chance.

if i were smarter, i would assemble directly a PC/NAS. it would be cheaper, and upgradable in the future. but i don’t know anything about RAID.

Yes, i was planning to use the old NAS for a remote backup, converted in a RAID0.

Hello all,

I’ve been using my 1019+ as a core for some time now. I don’t use many DSP to avoid using too many resources, and the interface might not be as quick as an external dedicated server, but it works well otherwise.

My advice:

  • Skip the cache, you probably don’t need it unless you do virtualization or stuff like this. You can always add them later if there is an update to use them for data.
  • Get a decent quality Sata SSD (256go should be more than enough even with a large library) in addition to 3 or 4 (if you can) HDDs in RAID 5 for your music.
  • Enjoy :slight_smile:

918+ is only 4 bays…1019+ is 5 bays.

so… opposite suggestion… less ram…

anyway, i’ll have 4 bay, just for storage. roon on an external USB SSD. it seems it’s a working configuration…

about RAID: i’ve read that RAID 5 can be … complicated. so, i’ll go for RAID1 (2+2). but this is offtopic.

Yeah hence the “If you can” :slight_smile:
918+ is more or less the same hardware, save for the extra disc. Meaning that it can be a decent Roon server, with a SSD and 3 discs in RAID 5. No need for m2 cache.

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I don’t think i mentioned less RAM… I have 8GB with my 1019+ so I can only speak for my config. I’d take the RAM if I had a 918+ for ROON + other stuff running on it!

Not with Synology, simple as ever!

I would just go with the SHR option for all 3/4 drives. USB SSD is slower - much slower than an SSD in a slot. messy is going to be the raid 1 2+2 for sure plus you only get N-2 times the drive space…for 4 x 4TB that’s only 8TB, SHR of 4 4tb will give you 12tb approx

Seriously if really want this as a core machine for now then I would get 3 x slightly larger disks in RAID5 or SHR and an SSD in the 4th slot. you will be maximising the performance of the core in this setup

Use the synology raid calculator here

I totally Agree

My Roon Core 1.7 runs on a Synology DS918+ and I think the performance is acceptable.
For your reference - this is my setup:

  • DSM 6.2.2
  • RAM 12 GB (expanded with standard RAM, not from Synology)
  • 3x 8TB HDD (audio files are stored here)
  • Roon Core installed on external 256 GB SSD conntect via USB 3
  • no installed M.2 cache
  • 11,900 albums
  • 207,000 tracks
  • Roon database folder size on SSD: 12.8 GB
  • two Squeezebox Touch as audio renderer

I am satisfied, even if this configuration is below the recommended one.

Hi, 2 questions:
-i thought the mx ram was 8GB. do you confirm 12 GB
-why just 3 HDs? as i understand you are not using the 4th bay for roon, that is installed in an external SSD (via USB 3).

the problem with RAID 5 is not about configuration. that i think is quite straightforward.
but i’ve read (so long ago…) that RAID 5 can have (more) troubles in case of a disk failure, when restoring data on a new disk. i’m not an expert, i’ll have to study about this before installing everything.

anyway…i was planning to go for the external SSD way… so, 4 HD for storage…

Niccolo, I confirm 12 GB RAM. 8 + 4 GB modules. Bay 4 is empty for further expansion.