Seagate Momentus XT hybrid drive and VMWare virtual disks

Question

I would like to know how does Seagate Momentus XT see virtual disk?

1. As a single huge file (size depending on virtual disk type)
2. As individual file within this virtual disk?

If the first one is true, then virtual machines on this drive work just as slow as if they'd be on everyday platters disk.

If the second one is true, hybrid drive speeds up virtual machines as well. You would likely see bootup times much shorter on a hybrid drive.

So users (or people that know its internals), which one is true?

Answer 1

The harddrive controller sits lower than the OS, so I would expect it to cache sectors and not necessarily certain files.

This makes more sense considering one of the biggest areas where the Momentus XT has shined is boot times.

But since the caching implementation isn't documented, you'd have to benchmark to verify this.

Edit:

This makes even more sense as Seagate claims the algorithm is OS independent.

Also here: http://forums.seagate.com/t5/Momentus-XT-Momentus-Momentus/Momentus-XT-Frequently-Asked-Questions/td-p/52701

The Momentus XT Adaptive Memory algorithm is an LBA-based algorithm that looks for small portions of data that take the drive a disproportionate amount of time to access. It then puts these portions of data in the Solid State storage for quicker access

Answer 2

XT hybrids work just like a platter drive, because they have platters, they also have a large amount of cache ram, the memory controller on the hard drive caches the most used/accessed files into the ram for fast loading into the motherboard memory. Virtual disc images are single files and are so large they may never get cached into the small hybrid ram, so there is no advantage.