C# Plugin: "SSD Optimizer" not Optimum

[eduncan911]

Is it possible to get the C# source to this?  I guess I can Reflect it and snag it if need be.

 

From the API, is it possible to force a file/rebalance immediately after a file has been copied to, say, an SSD like this?  There's a checkbox on the Settings tab that allows Balancers to force a re-balance.

 

The problem I am running into is my "SSD" drive, a 240 GB SATA6 drive, gets "full" very quickly when I move TBs around - and doesn't get "emptied" until a full rebalance is complete.  Which is annoying when trying to move 25 TBs around.  I'd have to complete disable this "SSD Optimizer" just so i can copy things.

 

Thanks!

 

[eduncan911]

Ok, I adjusted the settings to:

 

 

Notice the "Not more often than every" setting that I cleared.  It seems the SSD gets about 50% full now and is able to buffer the 120 GB of data, while balancing moves it off.  I am still evaluating it; but so far, that seems to be what is happening (I copy a new file to SSD, and Balancing copies the older file I just finished from SSD to pool at the same time).  

 

I determine this because Scanner shows the old 2 TB and 3 TB drives I am copying from at "60 to 80 MB/s"; but yet, Scanner shows the SSD moving at 180 MB/s, with another drive in my pool getting 100 MB/s.  E.g. 80 (write) + 100 (read) = 180 MB/s from the SSD throughput overall in Scanner.

 

Obviously, this will make a lot more "balancing" happening which has me concerned - I have 20 disks in my pool (about 60 TB) and "Spin Down" the drives to concern power (230 Watts vs 85 Watts idle).  

 

Would highly prefer "Balancing" to happen after hours, of even once a week as I got the room.  I jsut want the SSD used as cache, and then the file moved to another drive in the pool - where it waits to be "Balanced" later.

[Christopher (Drashna)]

I don't think the source for the specific balancer is there, but we do have sample source for creating your own balancer:

http://wiki.covecube.com/StableBit_DrivePool_-_Develop_Balancing_Plugins

 

 

However, one thing that I noticed is the ratio. The higher it is, the more aggressive it is about moving files out of the SSD drives. Try setting that to 100%. 

 

 

 

And I'm guessing that you're getting "out of disk space" errors specifically?  

If so, that may be because of where the limits are set on the SSD drives.  In the SSD Optimizer, try setting the "Fill SSD up to" to a much lower value. 

 

This setting sets the "real time placement limiters" for the drives. Once the drives get that full, it will start using other drives. Setting this to a lower value means that it should be better about forcing data off of the SSD drives, and about placing files on other drives when the SSD drives get full.

[eduncan911]

Ah yes, I had "Fill SSD drives up to" set to 98%.

 

I've now set that to 60%.  Will monitor.  But, that kind of goes against what I wanted to use a 240 GB SSD for... To cache 240 GB of files before it has to divert to the drive pool, not 140 GB (60%).

 

Shouldn't it divert to the drive pool anyways?  Even with 98% set?

 

And yes, "out of disk space" was the error I was getting.

[Christopher (Drashna)]

Well, the clarify here:

 

The normal strategy for filling drives is to place the files on the disk with the most (absolute) free space. 

 

The "Real time placement limiters" (which is what is configured by the "Fill SSD up to" setting) limit where files can be placed (instead of placing on any disk).  However, when the limit for these are exceeded, it resorts to using any drive. 

 

Additionally, since it checks the files with the real time placement limiters first, if you don't have enough space on those drives (the SSDs), it will give you the free space error.  By lowering the limits, it means that there is more "free space" reported to the system, and will resort to placing files on the other drives a bit sooner (helping to prevent the "free space issue").