StarWind Software

Is it possible to use multiple SSD drives for L2 cache? For example, instead of purchasing a more expensive 1.6 TB Intel P3700, is it possible to purchase two 800 GB Intel S3700 SSDs and get 1.6TB of L2 cache that way?

You can do that, I'm doing it with my lab build here. I have 2 x 128GB SSD's and operate them as independent L2 cache drives using one for one set of volumes and the other for a second set of volumes.
You could RAID 0 them together if you want one big pool of cache space but then you increase the chance of a SSD failure removing all L2 cache functionality from all volumes when/if one SSD fails. Keeping them as separate drives minimizes the impact of any one SSD failing as far as I am concerned.

Andy

Currently you cannot have separated SSDs to cache one LUN within StarWind. What you can do you can configure a software RAID in Windows from your SSDs and use resulting virtual volume to host StarWind cache file on

I'd rather keep the cache drives as separate entities to limit the perf impact if any one failed. At least then you can lose a cache drive and only a subset of your volumes lose L2 cache functionality.

For now that' the working plan for us: per-VM exclusive L1 caches and deduplicated per-data store L1 and L2 caches (shared). We'll see

AndyKnight wrote:I'd rather keep the cache drives as separate entities to limit the perf impact if any one failed. At least then you can lose a cache drive and only a subset of your volumes lose L2 cache functionality.

OK, so am I correct in understanding that you want to use >1 Flash drive as the L2 cache of one single StarWind device?
May I wonder what implementation scenarios do you see with that? BTW I have already informed R&D about your feature request.

Anatoly,
I didn't read into any of the posts that they want to dedicate a drive to a single device. I would like to speculate, that this might be a good place for lsfs on raw device, instead of ntfs on top. the cache drive would be able to bypass the ntfs filesystem overhead, i fit were allowed to be a raw device, and starwind placed lsfs on top of it. I also could see using this pool for multiple starwind devices, maybe assign a set of globaly available cache devices, and upon target creation, pick which one to use.

It is. I will make sure that this will be reported as the feature request to our R&D. Thanks for sharing your idea!