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Vlastimil Burián
Asked: 2024-09-30 05:35:17 +0800 CST

Does it make sense to use NVMe drives for our Synology NAS to act as a cache?

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I have a small business. With little previous knowledge/experience of NAS solutions. The budget was a bit of a problem, I have been capped to 40,000 CZK =~ 1800 USD. First, it may be best to tell you what solution I picked up:

Synology DS923+ with these plugged into:

  • Let me start with a UPS, which I already had for 3 months, signalling via USB to the NAS, (this was not part of the budget obviously);
  • The included amount of RAM was a joke, so I fitted it with 2x 16 GB ECC module (not from Synology);
  • I need just about 22 TB to tripple the previous poor solution, so I went for 4x 8TB HDD (not from Synology);
  • Finally, I fitted 2x 1 TB M.2 NVMe (not from Synology).
  • 1 Gigabit/s speed is ok for us, so I did not have to buy the 10 Gigabit extension;
  • (For completeness, I have a symmetric connection from my ISP with 100 Mbit/s down/and also up and both the router and main switch is not from Synology).

As for set-up, stating only the most important settings:

  • SSH access from my main Linux machine with public authentication;
  • Reliable and stable connection to the mentioned Linux machine via NFSv4.1;
  • Previous solution had only 2 bays 4TB each in RAID0, this time I struggled with my thinking, but in the end had set up RAID5;
  • I am well aware I should be going for RAID6 likely, but I would not reach the required capacity, it is a bit better than RAID0, right..;
  • As for the file system, I chose BTRFS just to try it out finally, it has nice features..;
  • Those two fast M.2 NVMe drives I have set-up as a cache for the volume, in RAID1 as read+write cache.

I was previously decided to use the M.2's in RAID0 as a very fast storage, and here we go:

  • I know how to unofficially do that, yet I resisted, and tried the cache first;
  • It appears to actually be more helpful, than I thought;
  • The use-case for this NAS is very wide, ranging from simple document sharing mostly inside local network with other people to saturating my upload link with high (legal) torrent usage;

Conclusion: Thanks to the heavy torrent use, if I am not mistaken, I believe utilizing those 1 TB NVMe's is a logical choice, but I tend to verify what I am inexperienced with.

So as for the formulation of my question:

Does it make more sense to use NVMe drives for that Synology NAS of ours to act as a cache than as a storage (which is unofficial with non-Synology drives, I know)? Thank you for reading the whole story! I hope to see some fact-based answers. Thanks in any case for your time.

Cache hits normally around 95%, image for the words:

cache hits

cache

1 Answers

  1. Best Answer

    When posting my question, I did not realize, I almost answered my own question.

    cache hits

    The cache hits are now stable 95% - 99%. So, in my use case, thanks to the torrenting involved mainly, using those M.2 NVMe drives as a cache proves to be highly effective right now, and I have a reason to believe it might stay this way.

    Conclusion: In my use case, yes, caching is very effective, and I will have it set-up like this until it changes, which could happen if we stop sharing legal torrents (Linux ISOs and alike).

    Hope it helps others with similar setups. Cheers!

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