Hello,

we have a new Poweredge R630, which arrived with 4 x 300 GB SAS spinning disks in RAID 5. Everything is fine with them.

We would however like to also use a SATA (SSD) drive (we have a far from exceptional Kingston SV300S3). We did insert it with a spare caddy and after configuring it as a new virtual disk, it seems fine. The only doubt I have is whether we can leave it without a SAS interposer in front of it. More specifically:

1) would the interposer increase its performances? Or would the bottleneck be the SATA: Rev. 3.0 (6Gb/s) interface of the SSD anyway?

2) does the fact that the SSD is attached as SATA hinder in some way the performance of the 4 SAS drives?

3) if we wanted to add an interposer, which part number should we buy?

Just for completeness: the performance as of now seems farily acceptable (but I have no clear benchmark in mind). In a sequential read test, it performs slightly worse than the spinning drives (~360 MB/s vs. ~595 MB/s), but in a random read/write test it clearly outperforms them (~10x the iops).