How are people using SSDs? …

I’ve just recently returned from China where I found a great deal of interet in all things SSD when it comes to storage. Much of our discussions centred on “what is the best use of SSD” and “where should I use SSD” and “how does Adaptec handle SSD”?

That got me thinking enough about this subject that I sat down and put a powerpoint presentation together just to deal with this issue. I’ve basically broken SSD usage into 4 areas, but I’m wondering if there are other uses that the IT community is thinking of that I haven’t considered. He’s my two cents worth …

Pure SSD environments
This sort of implementation is for those with deep pockets and the ultimate need for speed. Pure 6gb SSD (SLC of course) is the fastest storage system you can get today. Combine a 6gb card with good quality 6gb SLC SSDs and you have the best of the best. Of course cost is a major consideration, and it’s hard to get capacity using these drives, but you will get the best performance possible.

This sort of implementation pushes the RAID card to it’s limits, but that’s a good thing because our cards have been bored to death waiting for SATA drives for a long time now.

Pure SSD and SATA combination environments
This sort of implementation makes a lot more sense to me. Everyone has the need for speed, but also the need for large capacity. However not many people have the need for very fast large amounts of storage. So it makes sense to use a small number of SSDs to make a storage volume for your fast data and a large volume of SATA disks for all the other stuff that you need to store on your server.

The downside to this sort of implementation is management of your data. You have to work out what goes where and manage the capacities, making sure you are making the best use of your SSD investment.

Hybrid RAID environments
This is really a niche area of SSD use. In the past if I asked you to make a mirror from an SSD and a SATA drive you’d think I’m a few sandwiches short of a picnic. However on our RAID cards these days if you create a mirror from an SSD and a SATA drive, the card will write to both drives to protect the data, but only read from the SSD, giving blazing read performance. So write speed is not really impacted, but read speed goes up dramatically.

I’m finding people really interested in this for very small specialised servers such as Terminal Servers, and for high-end workstations where it takes a long time to build the software on the server … you don’t want to have a single drive in that machine because if it fails the cost of rebuilding the machine is more than the cost of the drive in the first place.

SSD as caching environments
This is my favourite and I consider it the best of both worlds. Having a large number of SATA drives in a pool, with an SSD drive (or two or three) acting as read cache for that pool, dramatically increases the random read speed of the drive pool.

This means that your random read speeds improve while the SATA drives handle the rest of the data flow such as sequential reads and writes and random writes. Management is a no-brainer as the card works out what should be cached and just handles the decision-making process for you.

So there’s 4 examples of SSD usage that I’m seeing on a day to day basis. What are you doing?

BTW: I recently saw a press release from a major drive vendor releasing 400gb 6Gb SSD drives to the market. While I don’t know the price of these yet, this has to have a major impact on the SAS drive market. Why use a very hot, very expensive, power hungry drive when you can use something that is faster, 2.5″, doesn’t get hot and doesn’t vibrate? Surely this is looking like the death of the SAS drive (or is it too early to make that call).

Finally, after going back and re-reading this for spelling errors, I notice that I hadn’t answered one of my questions at the top … “How does Adaptec handle SSDs” … the answer to that is simple. A drive is a drive is a drive. To our hardware RAID controllers (which are SAS controllers), a drive is simply a drive. We don’t care whether it’s a SATA, SAS, SSD (SATA or SAS) etc, to us it’s just a drive and we’ll run it to it’s maximum performance capabilities independent of whatever else is connected to the card.

Ciao
Neil