Re: [zfs-discuss] Sun Flash Accelerator F20
A word of caution, be sure not to read a lot into the fact that the F20 is included in the Exadata Machine. >From what I've heard the flash_cache feature of 11.2.0 Oracle that was enabled >in beta, is not working in the production release, for anyone except the >Exadata 2. The question is, why did they need to give this machine an unfair software advantage? Is it because of the poor performance they found with the F20? Oracle bought Sun, they have reason to make such moves. I have been talking to a Sun rep for weeks now, trying to get the latency specs on this F20 card, with no luck in getting that revealed so far. However, you can look at Sun's other products like the F5100, which are very unimpressive and high latency. I would not assume this Sun tech is in the same league as a Fusion-io ioDrive, or a Ramsan-10. They would not confirm whether its a native PCIe solution, or if the reason it comes on a SAS card, is because it requires SAS. So, test, test, test, and don't assume this card is competitive because it came out this year, I am not sure its even competitive with last years ioDrive. I told my sun reseller that I merely needed it to be faster than the Intel X25-E in terms of latency, and they weren't able to demonstrate that, at least so far...lots of feet dragging, and I can only assume they want to sell as much as they can, before the cards metrics become widely known. -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Sun Flash Accelerator F20
My post is a caution to test the performance, and get your own results. http://www.storagesearch.com/ssd.html Please see the entry for October 12th. The result page you linked too, shows that you can use an arbitrarily high number of threads, spread evenly across a large number of SAS channels, and get the results to scale. This is Sun's ideal conditions designed to sell the F5100. Now, real world performance is unimpressive. The results need to be compared to other Flash systems, not to traditional hard drives. Most flash, including Sun's trumps traditional hard drives. I'm issuing a caution because I think its a benefit. Look at Sun's numbers for latency http://www.sun.com/storage/disk_systems/sss/f5100/specs.xml .41ms Fast compared to hard drives, but quite slow compared to competing SSD. I've done testing with the X25-E (Intel 32GB 2.5" SATA form factor drives). I'm cautious about the F20, precisely because I would think Sun would be anxious to prove its faster than this competitor. I have not said its slower, only that its unconfirmed, and so my recommendation is to confirm the performance of this card, do not assume. Good advice. -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Sun Flash Accelerator F20
I agree, that assuming that the F20 works well for your application, because its included in the Exadata 2, probably isn't logical. Equally, assuming it doesn't work, isn't logical. Yes, the X-25E is clearly a competitor. It was once part of the Pillar Data Systems setup, and was disqualified based on reliability issues...in that sense, doesn't seem like a good competitor, but it is a competitior. I'm not here to promote the X-25E, however Sun does sell a rebadged X-25E in their own servers, and my particular salesman, spec'd both an X-25E based system, and an F20 based systemso they were clearly pitched against each other. As far as I'm assuming about Sun's .41ms benchmark methodology, really? am I sir? hardly. I start that as the basis of a discussion, because Sun published that number. Seemed logical. But I think we mostly agree, good idea to test. My intention was just to save anyone from disappointment, should they purchase without testing. I admit, I haven't posted here before, I registered precisely because google was showing this page as being a forum to discuss this card, and...just wanted to discuss it some. My apologies if I seemed too enthusiastic in my points, from the get go. -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Sun Flash Accelerator F20
"there is no consistent latency measurement in the industry" You bring up an important point, as did another poster earlier in the thread, and certainly its an issue that needs to be addressed. "I'd be surprised if anyone could answer such a question while simultaneously being credible." http://download.intel.com/design/flash/nand/extreme/extreme-sata-ssd-product-brief.pdf Intel: X-25E read latency 75 microseconds http://www.sun.com/storage/disk_systems/sss/f5100/specs.xml Sun: F5100 read latency 410 microseconds http://www.fusionio.com/PDFs/Data_Sheet_ioDrive_2.pdf Fusion-IO: read latency less than 50 microseconds Fusion-IO lists theirs as .05ms I find the latency measures to be useful. I know it isn't perfect, and I agree benchmarks can be deceiving, heck I criticized one vendors benchmarks in this thread already :) But, I did find, that for me, I just take a very simple, single thread, read as fast you can approach, and get the # of random access per second, as one type of measurement, that gives you some data, on the raw access ability of the drive. No doubt in some cases, you want to test multithreaded IO too, but my application is very latency sensitive, so this initial test was telling. As I got into the actual performance of my app, the lower latency drives, performed better than the higher latency drives...all of this was on SSD. (I did not test the F5100 personally, I'm talking about the SSD drives that I did test). So, yes, SSD and HDD are different, but latency is still important. -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Sun Flash Accelerator F20
There is a debate tactic known as complex argument, where so many false and misleading statements are made at once, that it overwhelms the respondent. I'm just going to respond this way. I am very disappointed in this discussion group. The response is not genuine. The idea that latency is not important, patently absurd. I am not going into the details of my private application, so you can pick at it. If you want to say latency has no relevance, you can defend that absurdity at the risk of your own reputation. The responses are not, in my opinion, genuine. Attacking Intel's spec sheet, when simultanously defending no latency #'s being release by another vendor? well I sent 3 emails in response earlier this morning, but I wasn't logged in, so I don't know if the mod will post them or not. Moderator, you don't have to, this will suffice as my last email. Guys, I don't have time to waste with you, and I feel that it is very wasteful to sit here and argue with people who either a) don't understand technology or more likely b) simply are being argumentative because they have a vested interest. Either way, I don't see genuine help. I am going to remove my account, and good bye! best of luck to everyone. -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
