Solid State Drives (SSD) are getting cheap and fast. So I’m putting 4 of them together in a Raid 0 array for a super fast MySQL server. The drives are just 30 gigs but cost only $75 each at NewEgg. Trying a 4k chunk size as these drives are unbuffered. I think that’s the sweet spot.
REVISED
Bottom line – it doesn’t work. I’m still investigating why but instead of being fast it’s extremely slow. Just formatting it with mke2fs takes 4 minutes and 54 seconds. These drives are made by OCZ and I think they are cooking the numbers on the flash drive speed. I think that the real numbers are more than 10 times slower than they specify.
#19
Yes, the SSD’s we’re talking about here are flash based.
DRAM is very fast and has unlimited writes, but its volatile. You have to have constant power and the cost of purchasing RAMdrives+sticks of RAM to populate them prohibitive.
Holy cow!! A real technology post on this blog.
Good info for a change…….
I don’t understand the reason for raid 0 here. Raid 0 stripes multiple drives to reduce seek (head movement) times. Since there are no physical moving heads on an SSD it should make no difference. Unless all you are after is a single 120GB solid state drive that is 4 times more likely to fail than any of the individual 30GB drives
“I don’t understand the reason for raid 0 here. Raid 0 stripes multiple drives to reduce seek (head movement) times. Since there are no physical moving heads on an SSD it should make no difference.”
I believe distributing data to more than one drive at a time would improve speed regardless of the technology involved.
I work with MTBF numbers every month. They should be taken lightly as they only represent the population and can be highly skewed one way or the other. MTBF is not a very accurate but it gives you an overall “feeling” of how your product or part will be doing.
@Alex Wollangk
For a laptop you can simply get a PCMCIA or express card CF slot for a few dollars and keep a flash card internally(and you can find fast CF cards cheap), and for a desktop search Newegg for a “5 port USB PCI Card”. These cards have 4 external and 1 internal USB 2.0 slot, which you can then use to attach your flash stick. I picked one up at Newegg last week for $10.50 including shipping. So while I don’t use Vista the internal boost you desire is quite easy to accomplish. Enjoy!
sETTING A RAID 1-2 would be nice, and would spread out the MTBF..
grouping the bandpass should accelerate the transfer also..
Im wondering how the mobo is dealing with it..Is it maxing out?
By what I have seen, the amount of power used in this config, is about the same as a Hard drive of the same size. so not allot of real savings.
I put an SSD in a previous generation MacBook Pro. The performance increase is amazing, especially compared to the stock 5400 rpm drive.
Details at:
http://osx411.com/installing-a-128gb-ssd-into-an-old-macbook-pro/
Bob
Uh John, you should have called Leo on his radio program and asked him for help!
Hmmm,what RAID controller are you using? What speeds are you actually getting?
I can imagine that writes would be slow but you should be getting great reads, although I haven’t used OCZ’s drives myself.
I’ll take the drives if you don’t want them…
Well from what I’ve been reading the buffered write rates are in the 150MB/s range, so 200 seconds for one drive on average – I presume you’ve already raid-ed them in which case you may be getting better than that actually. I would have to say formatting isn’t a good identifier for benchmarking though, it’s a constant write stream with very little reading.
Make sure that you are NOT putting any paging or heavy writing filesystems on it though. The random write/reads will ruin whatever possible performance gains you’ll get. I’d use it for OS system files and distributions and databases where the largest part of the system is read-only.
Now it would be interesting to have a secondary SATA hard drive holding your high TPS database files, with the ssds holding all of your lookups and low-write tables. I suspect it would be on par with caching it all in memory, though you still have the overhead of the SATA controller access.
Did you have some particular reason to strip it instead of going for a raid-5 config? With new drive types it’s far more realistic (and comfortable) to set them up as raid 5 so you can potentially hot-swap out a bad drive and not lose the whole array.
You actually should be able to use that raid box that John was pushing a few months back, I can’t remember but I thought it could handle raid-5.
I’m using Linux software raid and the motherboard has 4 SATA II ports. the drive is rated at 150/90 r/w speed which is reasonable fast. In Raid it should be about 4X that speed. What using real hard drives this works. So what I suspect is that those numbers are cooked and that in real life you don’t get that speed under load with random reads and writes.
Check out that macbook 128gb ssd upgrade.
After a while the mac crawled to a halt … defective blocks, ssd returned on warranty.
HD-Tach shows my 64 GB G.Skill drive is reading just below 150 MB/s with an access time of .2ms. Linear writes like copying a file to the drive gives me ~30-50 MB/s. The documentation says that I should be getting 155 MB/s max on reads and 90 MB/s max on writes. Doing a NTFS format (not a quick format) of the drive in Windows setup was near instantaneous.
What read/write performance you’re actually getting? Have you tried testing the drives individually to make sure you don’t have a bad one? That’s all I can think of.
I wouldn’t expect 4x performance since the seek times are already so low on SSD’s, but it should help with write performance.
Marc, what speed testing diagnostics have you tried? SI-Soft makes a good one, and there are several others. I’m not certain how they’ll work on SSDs, but it might be worth a try.
Are the raid drivers spec’d to perform this task?
the bios of the raid/sata controller should be accessible, did the drives auto detect ok?
SSD has a completely different “behavioral topography” from hard media. If the OS and drivers aren’t designed for that then it’s inefficient.
A combo of hard and SSD can work well, and will increasingly get better. Unfortunately, the Linux folks are well behind on this one and need to catch up.
Raid controllers use memory buffers to speed up the transfer rates on regular hard disks and Raid controllers can actually hinder SSD performace. Unless you get a specific type of Raid Controller for SSD performance then you wouldn’t see a performance increase you will actually see a decrease.
Why should it take a specific driver for SSD? It’s a SATA II drive. It should act like any other drive.
As to what speed test am I using – none. It’s just that a format process that should take 10 seconds is taking 5 minutes.