SSD Caching, Duplication, and File storage

[Shu]

Hi all,

I have 3 SSDs of various size (128gb, 480gb, and 1tb) that I want to use in multiple ways. I currently have a DP for my HDDs (3 drives of 4-8tb each). 

1. I would like to use the SSDs as a write cache for the HDD DP

2. I would like to have files permanently stored on the SSDs (I'm thinking steam library, temp folders for video editing). 

3. Some duplication rules for some folders that I want stored on the ssd (the video files for example) but I don't necessarily care if they are stored on the SSDs or not. 

At first, I thought I'd do an SSD DP and then nest it within the HDD DP but I'm not sure if the SSD Optimizer will see that as one ssd or the 3 (because I know it needs to see at least 2 when I have duplication set on those HDDs). I would like this approach as I don't really care *which* individual ssd the permanent files live on and doing file placement rules if I have to add them individually to the HDD DP sounds like more work. But I'm not sure if I will need to mount that ssd dp or if I can just have like an "SSD" folder in the parent dp and use that for the ssds

 

Let me know if I'm making sense or not and thanks in advance for the help!

[Shane]

Hmm. Tricky. I've done some testing; the SSD Optimizer balancer conflicts with the requirement to keep certain files on the SSDs because the Optimizer wants to flush the cache disks despite the File Placement rules (even if it does not do so on the first balancing run, it will do so on a subsequent run) regardless of the File Placement Settings in the Settings tab. I'm not sure if that's a bug or if it is working as intended... though I suspect maybe the former.

I'll play around with it some more and see what I can come up with.

EDIT: @Christopher (Drashna) is it possible to get the SSD Optimizer balancer to play nice with the File Placement rules? I've tried the various permutations possible in the Manage Pool -> Balancing -> Settings -> File placement settings section but even when it respects them on the first subsequent balancing pass it fails to do so on later balancing passes, i.e:

1. I set up a pool with the SSDs marked as SSDs in the SSD Optimizer balancing plug-plugin.
2. I create a "SSD" folder and set up a File Placement rule that any file in that folder should be kept on the SSDs.
3. In File placement settings I tick "Balancing plug-ins respect the file placement rules".
4. I copy files to the pool; they go into the SSD drives per the real-time requirement of the SSD Optimizer.
5. I start a balancing pass; the File Placement rules are respected and the matching files stay on the SSDs while the rest are moved to the HDDs.
6. I start another balancing pass; the File Placement rules are ignored and SSD Optimizer flushes all files on the SSDs to the HDDs.

#6 shouldn't be happening? Doesn't seem to matter whether the other File placement settings are ticked or unticked.

[Spider99]

Partition the larger ssd(s) so dp sees more than three

but dont add all the ssd's to the ssd optimizer plugin - so one or more are still archive disks so the placement rules will work

or use the third ssd as the archive disk and not part of the ssd optimizer

etc

etc

[Christopher (Drashna)]

@Shane  Yes.  From the notes for the balancer: 
 

Quote

* If you've created file placement rules that are attempting to keep files on drives that are designated as SSDs,
  then you should disable the "Unless a drive is being emptied" option, under the "File placement settings" category, 
  on the "General" tab. Otherwise, your File Placement rules will not be respected by this plugin (because it is 
  emptying the SSD drives).

@Spider99 Just keep in mind that StableBit DrivePool is aware of when different volumes/partitions are on the same physical disk, and will avoid placing duplicate data on the same physical disk.