Virtual System problem and question

Discussion in 'Returnil releases' started by cyberdiva, Jan 6, 2010.

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  1. cyberdiva

    cyberdiva Registered Member

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    I have recently started to use Returnil Home Lux version 3.0.6517.4958-REL on WinXP Pro SP2. I was stunned today to find that the amount of free disk space on my hard drive had gone way down. I did a search for large files and found one: Returnil's RVSYSTEM.CCH, which was more than 25 GB. I went into the Returnil program to try to understand why this file was so large. I had told Returnil to drop all changes on computer shutdown, I had NOT told it to start with Windows, and I had shut down my computer several times since I had used Returnil. So why should that file still have been on my system? Oddly enough, though I made NO changes as I was poking around today, suddenly my disk space went way up and the RVSYSTEM.CCH file disappeared. But it was clearly there days after I had run Returnil. Why?

    Also, I don't understand what percentage of my free disk space I should allot to the Virtual System. I accepted the default, 50%, but I don't understand why it should be 50% rather than, say, 10% or any other percent. As it happens, the 25+ GB RVSYSTEM.CCH file was approximately 50% of my available free disk space, but do I need to allocate so large a percentage? What determines how much I need? I looked in the User's Manual, but I could find no explanation of why the default is 50% or what would happen if I set it to, say, 10%. I'd be most grateful if someone could explain this to me.

    Thanks in advance for your help.
     
  2. Coldmoon

    Coldmoon Returnil Moderator

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    Hello,
    There is a new release version available: https://www.wilderssecurity.com/showthread.php?t=262118

    The cache starts as potential and not used space so this is actually illusory and due to the way Windows "sees" the properties of the file.

    What is actually happening is that RVS will reserve an amount of free space equal to whatever the maximum percentage for the cache is configured to be. By default, this is 50% of the available free space when RVS System Safe is activated. Though the space is reserved, it is not used unless it is required, and then, only that space that is absolutely necessary to clone the current changes.

    When you exited the virtual session (deactivated System Safe) and continued using the computer without the virtualization active, the "reserved" space was released back to Windows so you saw that happen when your HDD space "climbed" back to where it was previously. Though the space is not actually used as detailed above, it also makes the same space unavailable to malware at the same time... ;)

    The cache size is going to be a "loose" configuration that must be determined by the user. 50% is the default setting to ensure a good user experience "out of box" as a full cache can result in delayed write errors where Windows thinks it is out of disk space (another illusion as the cache is reset with a restart...).

    Think of what the setting implies by asking for a percentage of available free space rather than asking the user to specify a static size and how the actual amount of space could vary widely depending on the capabilities of the computer.

    Ex's:

    1. Older Windows XP system with a single, standard 40 GB HDD (no partitioning).

    Assume at least 15 GB could be used by Windows itself and you are left with 25 GB of free space available total. With the slider in RVS set for 50%, this means that your cache would only be able to grow to a maximum of 12.5 GB before a computer restart is required to reset the cache.

    2. New Windows 7 system with a 650 GB HDD with a single factory recovery partition of ~15 GB with Windows itself using a similar amount of space on the System Partition (usually the "C:\" drive). This leaves a total of 620 GB in available space. With the slider at the default 50%, this means the cache would be able to grow to a maximum of 310 GB before the computer would need to be restarted.

    310 GB vs 12.5 GB would obviously mean that the Win 7 system would have a greater potential for up time (time before a restart is required) than the XP system.

    What does all this mean?

    For most average users, the 12.5 GB may actually be sufficient and provide a good user experience (few, if any, restarts needed), but for the power user, this may be insufficient. So we recommend that users experiment with different settings to fine tune the maximum to fit their normal use patterns while providing enough slack to keep from having to reset the cache manually (cache is always reset after shutting the computer off).

    Mike
     
  3. cyberdiva

    cyberdiva Registered Member

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    Thanks VERY much, Mike, for your very prompt and helpful message. I'm still a bit mystified, however, since I exited the virtual session on January 3, turned off the computer several times between then and now, and still--three days later--found that humongous 25 GB RVSYSTEM.CCH file on my computer. So the space was **NOT** released for three days! That's really problematic.

    I guess I'm still not sure what is being cached. If I understood that better, perhaps I'd be better able to set the cache size in a reasonable way. What would constitute a "power user" vs. an "average user" in this situation? I often think of myself as a power user, but in this case I'm not at all sure.

    Many thanks for your continued help.
     
  4. Coldmoon

    Coldmoon Returnil Moderator

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    Older systems may take time to release the space, but will ask the team to investigate optimizing this process.

    All changes made to the System Partition during the current virtual session are cached. This means any document edits, new documents, a file downloaded or copied from another disk to the system partition, game saves/statistics, log files, new e-mails, configuration changes, error logging, ...etc. So it is very difficult to put into general terms as everyone's environment is different.

    Think about the difference in required space for the following two activities:

    1. Downloading and reading your current POP3 e-mail. Each e-mail would only represent a few KB's to a couple hundred KB's on average. Given this as the only activity on the system in this example, you might only need a cache size of a few MB.

    2. Downloading and editing video content. Each video segment or home movie might be anywhere from a few MB to several GB's in size, so the cache would need to be several orders of magnitude larger than what would be required in #1 above.

    Mike
     
  5. cyberdiva

    cyberdiva Registered Member

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    Mike, you are amazing! Thanks VERY much for another very rapid and very helpful response. Given what you say, I think I can probably make my Virtual System relatively small. Though I do download videos and the like, I probably won't be doing so while System Safe is enabled, since I'm confident about the videos I download and I do scan them before opening them. Other than that, I think the space I'll need is quite small. I use IMAP and web-based systems for my email, so I'm not downloading each one as I would with POP. In short, I think I'll switch from 50% to perhaps 10% and see what happens.

    BTW, I might note that I had a problem when I tried to upgrade to the most recent version of Returnil. I had forgotten that I should turn off my security software first, and the process ran into problems from my firewall. Not only didn't the upgrade occur, but the uninstalling that was apparently automatically done as part of the upgrade didn't complete. When I turned off the security software and tried again, I was told that the uninstallation had been incomplete, and that I should completely uninstall before installing the new version. The only problem is that Returnil was no longer listed in Add/Remove programs! I finally decided to go back to a restore point from yesterday. There WAS one from today, but I wasn't sure whether it was made before the uninstallation began. Oh well.... Never a dull moment. ;)

    Again, MANY MANY THANKS for your help. :thumb:
     
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