Slashdot Mirror
AOL Spends $1M On Solid State Memory SAN
Lucas123 writes "AOL recently completed the roll out of a 50TB SAN made entirely of NAND flash in order to address performance issues with its relational database. While the flash memory fixed the problem, it didn't come cheap, at about four times the cost of a typical Fibre Channel disk array with the same capacity, and it performs at about 250,000 IOPS. One reason the flash SAN is so fast is that it doesn't use a SAS or PCIe backbone, but instead has a proprietary interface that offers up 5 to 6Gb/s throughput. AOL's senior operations architect said the SAN cost about $20 per gigabyte of capacity, or about $1 million. But, as he puts it, 'It's very easy to fall in love with this stuff once you're on it.'"
What is surprising to me is not the amount of money spent on what was bought, but the fact that AOL has any performance issues at all. They still have users? They have an entire database of users?
You can't handle the truth.
As a DBA, I would love to have solid-state storage instead of needing to segment my databases properly and work with the software dev guys to make sure we have reasonable load distribution.
Where can I get someone to pay a million dollars so I can do substandard work?
---
According to the latest ruleset, this post should be modded as Vorpal Flamebait +5.
You can read more about that here:
http://www.google.com/search?q=High-Speed+Data+Link
My impression has been that this has been what has been going on for some time now with all the larger database operations, and one of the reasons why SSD have not yet come down in price is that all the best units and tech are going to the big companies as fast as they can get it from the manufacturers. I wouldn't be surprised to see someone like Google saying something like "yawn, 50TB" and saying that they have PETABYTE versions already out there.
If you run a Database of any size, especially ones with large read to write ratios, SSD would only make things faster. And speed counts.
Agent K: A *person* is smart. People are dumb, stupid, panicky animals, and you know it.
Now we just need something cheeper then 20$/GB
Actually, the price was the most interesting part of this:
at about four times the cost of a typical Fibre Channel disk array with the same capacity
Four times the price and, what, ten? A hundred? times the IOPS? That makes NAND pretty much a no brainer for any heavy-use database.
I am TheRaven on Soylent News
hey could've done it cheaper.
It's AOL, would you actually expect them to make intelligent, informed decisions?
AccountKiller
I wonder what the read/write rating is vs. a hard disk?
Wikipedia puts flash at 1,000,000 program-erase cycles
What one fool can do, another can. (Ancient Simian Proverb)
It's very easy to fall in love with this stuff once you're on it.
I said the same thing about coke in the 70's....
I guess what i'm saying is, no one loan money to AOL until they admit they have a problem.
Google found differently in their massive hard drive survey... sometimes drives would just up and die with no SMART warnings. Also the most common SSD failure-case is lack of writes, at least you can retrieve data off the drive as opposed to a completely opaque device if the platter is frozen.
Make sure everyone's vote counts: Verified Voting
Google found differently in their massive hard drive survey... sometimes drives would just up and die with no SMART warnings. Also the most common SSD failure-case is lack of writes, at least you can retrieve data off the drive as opposed to a completely opaque device if the platter is frozen.
Yeah, I've seen quite the opposite. Let me preface this with saying that I'm strictly talking about consumer and midrange drives, I've seen very few SCSI and SAS drives die without warning.
In the past 10 years, in a company with about 200 nodes, I can literally count on one hand the amount of hard drives that have given any SMART warnings leading up to their imminent failure. They pretty much always die while the OS accumulates log entries of bad blocks and I/O errors. Most of the time it was either death by shock, or death by manufacturer defect (Maxtor!). The former, SSD drives are pretty much immune to BTW. I would prefer an SSD in a road warrior or college student's laptop any day over a conventional HDD.
grep -iw skynet
They wanted performance and went *RAID 5*? That pretty much sums the entire approach up. Let's not optimise the application first, the database second, but instead hide the problem by throwing hardware at it. Then what we'll do is use a RAID configuration that hobbles the write performance of the arrays and lets not mention what happens to performance when we lose a disk (don't say it won't happen).
Sure, RAID 5 is the answer to somethings, but not when the question is database *PERFORMANCE*.
Also - latency is more important than IOP/s. I don't care how many IOP/s you can do, if you're latency is high, the performance won't be. Most garden variety storage engineers don't seem to grasp this concept.
It is hard to know anything for sure with this limited amount of info. But it appears to me that they have not accomplished such a great feat.
I put together a server this year that pushes over 9 GB/s. I did this with a mere 150 2.5 inch drives. (144 raid 10 + 6 live spares). This was SAS 2.0 of course, because in the real world SAS kicks FC's A**.
We found that the real bottleneck to throughput is not the drives and not the SAS cards. We have 8 SAS 2.0 lanes coming into each card, multiply that by 6 cards, and you have a heck of a lot of potential.
No, the real problem is you saturate your PCIe slots, and chipsets sometimes choke when you feed this much data. So, the chipset and PCI-e bus tend to be the restraining factor, not the archaic rotating platters.