msata slower with large files

Drobo - End of Sale Drobo 5N
1

i find if i’m copying files over which are all >4gb in size, its actually slower with the msata drive inserted

sometimes its just slower period other times there are big pauses during the copy phase (i assume its the msata making space for new files)

having no msata i had a solid >80MB/s write, with it anything between 15-50MB/s, after having moved >50GB of data at once

if the drobo sits idle for a while in the beginning it will hit the 80-90MB/s with the msata because i assume its made room by then

anyone agree?

2

http://www.drobo.com/how-it-works/data-aware-tiering/

Tiering on Smaller Drobos
The mSATA SSD is used to accelerate smaller and random reads from the Drobo, while the HDDs are used for storing and streaming larger data such as photos, video, and user documents.

I don’t see anything talking about writes to the Drobo with MSATA, only the reads from the Drobo. I also am unsure what they consider smaller reads, though I would think anything over 50meg would be a larger read.

I don’t have the MSATA so I don’t have any experience with them. Based on what I read about the life expectancy of MSATA in a Drobo I opted out of them, that and the fact the Drobo 5N is plenty fast enough for media streaming to multiple devices without it, I just don’t suggest trying it with “green” drives.