2x SSDs in RAID0 as fast cache?

[MC Hamster]

Just wondering how possible this is? Am still running an old 1366 setup before Intel SRT came along with the fast caching and am pondering my options for a new build. I believe there's third-party software around that can do it, but I was hoping for an "in hardware" solution if it's available..

I'm well and truly over having to manually shuffle hard drive space about with my existing setup, but am well and truly addicted to SSD speeds.. I'm wondering about the possibility of pairing a couple of smaller SSDs into RAID0 and setting them up as fast cache in front of a big chunk of spinning disk (possibly a RAID in itself..)

Is there a 'hardware' solution (at least.. that's OS independant) around that can do that? If not, what's recommended for software? I've seen reference to VeloSSD as a possibility, but are there others out there to consider?

Appreciate the advice!

 

[MC Hamster]

Oh, and a part 2 for this.. what sort of interface options would there be for this? I'd think SATA 6GB would likely be getting flooded at that point, meaining SATAe would be desirable... but if you're running (hypothetical) a high-end pair of video cards (eg sli 980s), they'd be contesting for bandwidth there too? Problems likely from that?

 

[Essence_of_War]

At the point where you're considering buying multiple lower capacity SSDs to RAID-0 for a fast cache, I'm wondering why not just buy a single large SSD. Not only are SSDs typically faster at larger capacities, they're also more affordable since you're not paying multiple times for packaging/controllers/etc.

On top of that, unless you have very particular workloads, the perception of speed from an SSD comes more from the impressive random read/write performance than from the sequential, and RAID-0 is likely to only significantly improve the sequential performance.

Without more specifics about your set-up, workload, etc, it's hard to give specific advice. ZFS, for example, natively supports the sort of hardware storage tier-ing you're describing. You can throw a few SSDs in, mark them as for L2ARC and/or SLOG, and suddenly you're getting a bunch of additional read/write caching. My guess is that this is not what you're interested in, though.

 

[MC Hamster]

Hrm.. fair call. RAID0 may well be unnecessary. This'll be for a windows box, so as nice as it would be, ZFS isn't really an option (I'm a bit of a linux guy myself, but a buddy that's big on solaris was raving to me about it years back).

Still.. is >64GB cache from Intel's firmware an option yet, or is it still limited there?

 

[Jovec]

Just buy a single SSD. 500GB can be had for $200-$250 and you'll have zero headaches. ZFS is mis-marketed. L2Arc will just eat RAM, and if the ZIL fails (or vdev) so does your pool.

If you have demanding needs maybe something other than basic SSDs are called for, but there is a danger zone that exists between a single drive and full and proper ZFS/RAID/NAS/SAN solution that countless people lose data in.

 

[jumpncrash]

with certain LSi raid controllers you can have an SSD run as cache for your hard drives, not sure which models though, I know the 9271-41 with cachecade module does, but it's most likely out of your price range

 

[dave_the_nerd]

The PERC H710P Mini will let you specify SSD(s) to use as a cache. I think it tops out at 256 or 512GB of cache thought. (I forget; it's been a while since I set that machine up. It's using a 120GB SSD as a cache drive for 2x 700GB 15ks, and when we baselined it, it was... fast.)