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Thread: CEP2 and HDD speed.

  1. #26
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    I've had crashes with both a Win 7/Intel/Indilinx combo and a Server 03/Intel/Sandforce machine.
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  2. #27
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    Quote Originally Posted by fallwind View Post
    I've had crashes with both a Win 7/Intel/Indilinx combo and a Server 03/Intel/Sandforce machine.
    Interesting. I heard and read a lot about the excellent quality of the Sandforce controller for SSDs. It seems it is not so perfect.
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  3. #28
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    FWIW I ran Linux on an SSD(OCZ 32GB) with an i7-860 and it crunched 8 WUs at a time without issues.



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  4. #29
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    Holy hard drive thrashing batman!

    So, I decided to do a little test with CEP2 work units tonight since I got my SR-2 rig up and running. I set up Boinc to crunch 16 threads of CEP2 simultaneously. I also installed HDDLED to monitor the read and write speeds and total bytes since last bootup. The intent was to help me win that sapphire badge asap! I also wanted to see how bad the hard drive thrashing would be.

    Well, I accidentally left my computer crunching all night last night and this morning when I woke up I found that I had written 380GB of data to my C drive. The drive is an SSD, so I'm not too thrilled about my little oopsie. I decided that I'd move my boinc data folder to my trusty ANS-9010 with 32GB of RAM and set up a RAID-0. The drive is not used for anything except for Boinc data for the following numbers. All WUs were previously downloaded.

    First I started up my gpugrid.net to get a baseline of how much data gpugrid.net reads/writes when it's crunching. After 2 hours the numbers were in: 350MB read, 317MB written.

    Next, I unsuspended my WCG project. Within seconds 2.5GB of data was written. There was no network activity, the 2.5GB of data appears to be part of the process of starting a thread. I checked my folder size, and it had only increased by about 40MB from 2 hours before.

    Then, I sat around for an hour. After an hour I took another look...



    HOLY CRAP! Is this thing for real? 27GB!? Gentlemen, if you love your SSD, do not try to run CEP2 WUs on it. Running 16 threads appears to generate about 1.5GB per thread per hour. Perhaps these ACard RAMdrives have a very useful function for me after all. They don't "wear out" like SSDs.

    One thing to look at is the rate kb/sec of the screenshot. I sat and watched the write rate to see what was going on. It turns out that 8-17MB are written every second. Every second. Not intermittently, but constantly. For those of you wanting to crunch CEP2 work units, I highly recommend against using an SSD if you want your drive to have a reasonable life span. I did try changing the checkpoint time from 300 to 600 seconds, it didn't appreciably change the size of the writes.

    I considered enabling the NTFS file compression for the boinc data directory. The files do compress quite well(about 40% saved). However, the extra CPU usage would slow down the performance of Boinc WUs.

    One big penalty is taken when you suspend and restart the threads(such as during a reboot). For whatever reason, 2GB+ gets written to my drive every time I reboot or when I unsuspend the WCG project.

    For those of you that DO use SSDs, I'd highly recommend minimizing the number of times you allow Boinc to suspend your tasks and try to minimize your reboots.

    I'm leaving my cruncher on tonight to see what happens to the totals for reads and writes. Stay tuned!
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  5. #30
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    Yep, the read/write activity is pretty crazy with CEP2. I'm using SSD's in 3 machines running this project, but I installed them as secondary drives, the only thing on them is BOINC, so the primary drive is spared the thrashing. I caught a good sale on the SSD's so I'm not too worried if they die.
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  6. #31
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    Quote Originally Posted by josh1980 View Post
    Well, I accidentally left my computer crunching all night last night and this morning when I woke up I found that I had written 380GB of data to my C drive.
    I disabled the CEP2 project for a week, planning to start again in about 2~3 weeks.

    My case was not different:

    Quote Originally Posted by Metroid View Post
    SSD host writes before the CEP2 project 1.2T, after 5 days 8 work units 3.3T.

    Pagefile is disabled so it uses the ram, now imagine if the pagefile was also enabled on the SSD
    9~10 days 24/7 CEP2 8 work units.
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  7. #32
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    Quote Originally Posted by Metroid View Post
    SSD host writes before the CEP2 project 1.2T, after 5 days 8 work units 3.3T.

    Pagefile is disabled so it uses the ram, now imagine if the pagefile was also enabled on the SSD
    How much RAM do you have? I run a quad-core, with 8 GB RAM and a generation 1 SSD. It runs up to 4 CEP2 work units at a time, and while I see a lot of disk activity, it is nothing like that. I have the pagefile set to 1 GB minimum, and it has never increased beyond that. But I don't use that PC for anything except WCG and Folding@home, so no games or even web browsing.

    And I am using Win7 64-bit, which can make use of all of the memory. Are you using a 64-bit OS?
    My CPU efficiency on BoincTasks shows up at 96% on CEP2 jobs, so it is not thrashing much. But it took a firmware update on my SSD to get that.
    Last edited by JimF; 11-25-2010 at 05:36 AM.

  8. #33
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    Quote Originally Posted by JimF View Post
    I have the pagefile set to 1 GB minimum, and it has never increased beyond that.
    Pagefile = hard drive space and speed + latency. The pagefile does not increase, in your case if the pagefile is used in full then the OS will use the ram memory but it will not tell you that the ram is being used and yes cached. It is good to leave the pagefile to a minimum, ram is faster than pagefile / hdd's and most ssd's. Only drawback for some programs is that ram is volatile and pagefile is a written cache.

    And I am using Win7 64-bit, which can make use of all of the memory. Are you using a 64-bit OS?
    Yes.

    How much RAM do you have? I run a quad-core, with 8 GB RAM and a generation 1 SSD. It runs up to 4 CEP2 work units at a time, and while I see a lot of disk activity, it is nothing like that.
    I'm using CrystalDiskInfo http://crystalmark.info/software/Cry...o/index-e.html to check host writes.

    Commit is the ram being used.

    Cached ram is there if needs to be used, the process may or may not have being killed.

    Available - Cache = Free

    I would be grateful if you could check how much cached ram you have while using BOINC with 4 CEP2 work units. In my case used to be between 800~1.280MB of cached ram per work unit.
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  9. #34
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    Quote Originally Posted by Metroid View Post
    Pagefile = hard drive space and speed + latency. The pagefile does not increase, in your case if the pagefile is used in full then the OS will use the ram memory but it will not tell you that the ram is being used and yes cached.
    I have the maximum set at 4 GB. If it needs more, it should use more.

    I'm using CrystalDiskInfo http://crystalmark.info/software/Cry...o/index-e.html to check host writes.
    I just tried it, but don't see much info on my SSD. Maybe because it is Gen 1, running in IDE mode?

    I would be grateful if you could check how much cached ram you have while using BOINC with 4 CEP2 work units. In my case used to be between 800~1.280MB of cached ram per work unit.
    I am not sure how to get the ram per work unit, but I am running 2 CEP2 jobs now (along with CCW and HFCC), and Task Manager shows 2090 MB cached. Is that what you want?

  10. #35
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    Quote Originally Posted by JimF View Post
    I have the maximum set at 4 GB. If it needs more, it should use more.
    The file is hidden in your hdd or ssd. It may only use more if you set it to System Managed Size which I would not recommend. If you set the pagefile then the Pagefile will not increase as it goes.

    I just tried it, but don't see much info on my SSD. Maybe because it is Gen 1, running in IDE mode?
    Strange, could be, probably somebody that also has the generation 1 could help us with this. I'm using the AHCI mode.

    I am not sure how to get the ram per work unit, but I am running 2 CEP2 jobs now (along with CCW and HFCC), and Task Manager shows 2090 MB cached. Is that what you want?
    Yes, that is enough. Now when both tasks get 100% don't set any other CEP2 work units, set others units now go to the task manager, you will see that your cached ram has decreased significantly, so that amount was freed from those processes.

    That is just the ram. SSD used space = almost the same amount of cached ram.

  11. #36
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    But I can look at disk activity in Resource Monitor, and the writes seem to be averaging about 1 MB/sec. Assuming it would be about 2 MB/sec for 4 CEP2 jobs, that is about 200 GB/day, which is nothing to sneeze at, but probably won't kill the SSD anytime soon. (There is in addition a lot of disk activity for about 5 minutes after a CEP2 job starts, but that can't affect the total much.)

    I think the write endurance on these flash chips is something like 100,000 writes per cell (it probably goes down for the later generation drives), so with a 30 GB SSD and good wear-leveling, I should be good for 15,000 days or 40 years. There are factors that can affect that either way, but it should be long enough for my purposes.

    PS - I have left out write amplification, which will reduce this by a factor of maybe 10 - I don't know what it is for these drives, but on the other hand most flash chips last well beyond the specified value.
    Last edited by JimF; 11-25-2010 at 07:49 AM.

  12. #37
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    Well, I left my machine unattended for 12 hours and racked up an amazing 359GB written to the drive! I'm going to leave CEP2 for this machine only and disable it on all of my other machines. The hard drive usage is just... crazy.

    -Josh

  13. #38
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    One way of reducing writes is by use of a write cache. And writing in larger blocks should help my Gen 1 SSD cope with all the I/O demands better (I hope). At any rate, FancyCache is in beta now, but free to try out for 90 days.
    http://www.romexsoftware.com/en-us/f...che/index.html

    One user reports that the use of delayed writes will extend the life of his SSD quite a bit:
    http://www.romexsoftware.com/bbs2/en...php?f=25&t=647

    I have used it thus far with limited success, since it likes to BSOD under certain circumstances that I won't go into here, but am going to try it again with different drivers. If you want to cache only a single volume (one partition on one disk), they recommend the Volumes version. If you want to cache all the partitions on the disk, or more than one disk, use the Disks version.

    It is also discussed at some length on the OCZ forum with respect to the Vertex 2 by the way.
    http://www.ocztechnologyforum.com/fo...ght=fancycache

    Good luck, and remember that it is in beta.

    PS - It works now, using the Intel SATA (IDE) drivers instead of the Microsoft ones, and probably more importantly using the Disks version rather than the Volumes version. It was suggested on their forum that the Disks version might be a simpler algorithm, less prone to crashes. But whether it actually reduces writes on CEP2 is another matter, since that will probably depend on whether new data can update old data in the cache before it is written to the disk, or various other factors that I know nothing about. But at least it should help consolidate the writes for less "thrashing" when multiple CEP2 jobs are running.
    Last edited by JimF; 11-27-2010 at 09:26 AM.

  14. #39
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    I'm currently at about 36 hours and 1.21TB!

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