You guys are joking about 20MB max with out BBU, right?
RAID 5, maybe, but any non-parity RAID set should fly.
I've got six year old drives attached to the SATA2 ports in one of my whiteboxes that will do ~60-70MB/s write, np. VMFS and all that. With SSDs the bus is the limit, VMFS doesn't need BBU for good write speeds. It just needs good drives.
And a raid controller that doesn't have issues, evidently.
I am having performance issues with my M1015 (now flashed to 9210-8i IR) and seeing simply horrible write speeds on small block sizes. It took nearly twenty minutes to create a 50GB eager zero'd .vmdk! The drives are "only" Momentus XTs in RAID 1, but that is no excuse for performance that is that bad.
ATTO Benchmark shows horrible, I mean horrible performance on small writes, and it doesn't really improve much until we are up to 32k block size+. It is about an order of magnitude slower than it should be with smaller writes. Larger write chunks bring performance up to what it should be.
Latency is also atrocious, 100ms+ being the norm for writes, as viewed via the VMware client.
Again, testing in my other white box shows performance in line with what it should be.
I am going to try the async driver later to see if that improves performance at all.
If not... well. I am not sure what I'll do at that point. Be very disapointed?
******
More education on my part - I now know what you are talking about.
It appears that with many onboard adapters that *work* with ESXi, write caching using the onboard volatile memory (8-64MB or so) is left enabled. Same is true with Windows Server.
Now, you take this particular controller, for example, and when you use it the cache on the drives is disabled entirely.
This severely retards performance of the drives in nearly all I/O situations. If you had an SSD RAID group, it would likely still be very functional.
With spindles, however, it is going to perform very poorly. As evidenced by the OP and myself.
Note to the internet - only buy this adapter for use with SSDs. Spindle peformance with the IR firmware and RAID is horrible on the 9210-8i.