Will I benefit from SSD write cache?

[Mayfair]

I have a new 920+ and 2x16TB Ironwolf Pro drives and have noticed a constant disk activity attributed to docker containers I am running. The NAS Nevers stops writing at the rate of 400-600KB/s.
Containers are Sabnzbd, Sonarr, Radarr, Prowlarr. Presumably it is logging activity.
Will write cache drives help to quite down the constant drive 'rumble' in this use case?
I have seen recommendations on this forum for the Samsung 970, so I may pickup a pair of those if it will settle down the spinners in the NAS.

Thanks!

 

[Rusty]

The NAS Nevers stops writing at the rate of 400-600KB/s.
Containers are Sabnzbd, Sonarr, Radarr, Prowlarr. Presumably it is logging activity.

Those apps have a 15min schedule to check for new releases, changes on your current content and in return make "the noise" all the time.

The cache will help with any frequent data request depending on what volume you bind it to, but it will have a benefit for typical "client-server" solutions that have a DB in the background (like Plex for example). In this particular case, it might be beneficial from a speed perspective, but not sure it will help in keeping your main drives from rumbling. Remember, the cache is still just cache, data changes, still need to be written to your main drives.

 

[Mayfair]

Those apps have a 15min schedule to check for new releases, changes on your current content and in return make "the noise" all the time.

The cache will help with any frequent data request depending on what volume you bind it to, but it will have a benefit for typical "client-server" solutions that have a DB in the background (like Plex for example). In this particular case, it might be beneficial from a speed perspective, but not sure it will help in keeping your main drives from rumbling. Remember, the cache is still just cache, data changes, still need to be written to your main drives.

Thanks for your comments. I see the 15 min checks going out in the logs, that makes total sense, although in my case I am see a constant a 20-50 IOPS a second and somehow am wondering if I am misconfigured.
Not sure how often Syno flushes the cache to HDD, is it fairly constant? Random I/O comes in , gets staged and sequentially written to disk?
Rather than a cache then perhaps I might benefit from a SSD drive in one of the drive bays as the home directory for docker. I know the lifespan of a SSD is not as long as a HDD, however I have run a similar setup for 8 yrs on an old windows system on a SSD and not killed it yet. This new setup is to replace that old system that I expect to die at any point

 

[Rusty]

I know the lifespan of a SSD is not as long as a HDD, however I have run a similar setup for 8 yrs on an old windows system on a SSD and not killed it yet.

I was about to say the same. SSD will surprise you for sure, but ofc it will depend on what you are running on that drive in the end.

From my testing, having a cache array will be beneficial in specific scenarios, and compared to a proper SSD array it will not be able to compete. So if you can, go with an SSD array (or a single drive), and save your $.

The cache might be good if you are certain you will not move away from HDDs, but the way things are going, running a cache array in a 4bay unit might not be something that will pay off in the long run. Again, it depends on what you expect from it.

Personally, I have dedicated NAS units that are all flash (SSD) and run apps and services on those. Separate units are capacity storage units that run HDDs only. Tested both NAS with all-flash and HDD+cache. SSD always came on top (ofc it depends on the CPU and RAM of the NAS, but when comparing the same NAS, SSD always wins).

 

[Mayfair]

I was about to say the same. SSD will surprise you for sure, but ofc it will depend on what you are running on that drive in the end.

From my testing, having a cache array will be beneficial in specific scenarios, and compared to a proper SSD array it will not be able to compete. So if you can, go with an SSD array (or a single drive), and save your $.

The cache might be good if you are certain you will not move away from HDDs, but the way things are going, running a cache array in a 4bay unit might not be something that will pay off in the long run. Again, it depends on what you expect from it.

Personally, I have dedicated NAS units that are all flash (SSD) and run apps and services on those. Separate units are capacity storage units that run HDDs only. Tested both NAS with all-flash and HDD+cache. SSD always came on top (ofc it depends on the CPU and RAM of the NAS, but when comparing the same NAS, SSD always wins).

Thanks. I have a 216+ (5 yrs old) with 2x8TB HDD that is my main backup/storage/archive. I just setup the 920+ with 2x16TB initially to act as my media box and have a shadow copy of my critical 216+ data on it too (I have several other backups of critical data btw but that is another discussion ).
Would you recommend I add a SSD or two to the 920+ as volume_2 and move my docker directories to that? And if I grow into those bays then perhaps go with a dedicated unit? I started to look at small form factor Intel NUCs for this purpose but that would be costly and frankly another 'science project' to setup.

 

[Rusty]

Would you recommend I add a SSD or two to the 920+ as volume_2 and move my docker directories to that? And if I grow into those bays then perhaps go with a dedicated unit?

It all depends on your needs, both from a service/app point as well as your storage. So I guess it will be up to you and your needs/budget to have the final voice on this one. I can only say that separating apps on an SSD array and data on HDD has been a much better experience than having it all on HDD+cache.

 

[Mayfair]

It all depends on your needs, both from a service/app point as well as your storage. So I guess it will be up to you and your needs/budget to have the final voice on this one. I can only say that separating apps on an SSD array and data on HDD has been a much better experience than having it all on HDD+cache.

Thank you. Can you recommend a SSD for this purpose? I am seeing Seagate Ironwolf SSD NAS drives, both Pro and non Pro, I don't expect a heavy volume of writes more like a constant small stream of data like I am currently seeing 300-600KB/s

 

[Rusty]

Thank you. Can you recommend a SSD for this purpose? I am seeing Seagate Ironwolf SSD NAS drives, both Pro and non Pro, I don't expect a heavy volume of writes more like a constant small stream of data like I am currently seeing 300-600KB/s

IMHO, I would go for the best warranty you can get. 920+ will not utilize the full potential of any SSD on the market that can go over 600MB/s (and that's most of them), so don't throw crazy amounts on them. I use WD SSDs with 5y warranty and that's what is beneficial for me.

I had them so far for about 20 months with 16k hours of power-on time, and health is still 100%. I can't say anything for the Seagate drives as I do not use those, and haven't had the opportunity to test out the SDDs as well.

In any case, focus on capacity and warranty. As for compatibility, they will all work 99% of the time, as 920+ is not affected by Syno's new HDD policy.

 

[Mayfair]

Great suggestion on the WD drives, they are considerably cheaper than Seagate. Do you run non-raid for this disk? And if I go for a single disk and want to raid it out later that is destructive, correct?

 

[Rusty]

Great suggestion on the WD drives, they are considerably cheaper than Seagate. Do you run non-raid for this disk? And if I go for a single disk and want to raid it out later that is destructive, correct?

I run it in raid1, but in your case you can start with a single drive in SHR. This will allow you to go from one drive to 2 drive in shr that will eventually be a mirror situation for that single drive. Capacity will still remain the size of one drive and you will not have to start fresh or destroy your volume.

 

[Mayfair]

I run it in raid1, but in your case you can start with a single drive in SHR. This will allow you to go from one drive to 2 drive in shr that will eventually be a mirror situation for that single drive. Capacity will still remain the size of one drive and you will not have to start fresh or destroy your volume.

Thank you for the guidance. I just ordered a 1TB WD Red NAS SSD and will start with a single drive in SHR setup as you suggested. I appreciate the help.

 

[Rusty]

An excellent choice! Enjoy!

 

[Robbie]

I can only say that separating apps on an SSD array and data on HDD has been a much better experience than having it all on HDD+cache.

No kidding - an all-SSD volume, supported by spinners as required, is the way ahead.

 

[Coop777]

Certainly, a complete SSD disk array would be the fastest and give the best performance, however depending on your storage needs, spindle drives still maintain a cheaper cost per GB than SSD's and SSDs aren't even available to buy above a certain size.

 

[Mayfair]

Certainly, a complete SSD disk array would be the fastest and give the best performance, however depending on your storage needs, spindle drives still maintain a cheaper cost per GB than SSD's and SSDs aren't even available to buy above a certain size.

I ended up buying a single 1TB SATA SSD that I slotted into one of the free bays of my 920+. It is volume2. I set it up as a single SHR member and if all goes well, I will likely buy a second one and build out a redundant set.
I have yet to migrate my containers from volume1, presumably I would shutdown all running docker instances, change the shared volume for /volume1/docker/ to /volume2/docker/ and then fire them back up after making changes to the docker-compose mount locations.