Drive corruption on a multi boot system

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Yozzer
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Drive corruption on a multi boot system

Post by Yozzer »

I only had primocache active on Windows 7 on my multi boot PC, which is installed on an 256gb ssd, most of the programs are kept on another drive to save space, and this has become my main system. On this main system I have Primo configured to provide drive D, (standard hard drive), with a 5gb L1, cache, and 12gb L2, no deferred write, (on a partition on the 256gb ssd). I do not have any cache configured for drive C.
I found sometimes, after booting from one system to another, when returning to Windows 7, there had been drive corruptions on drive D requiring the drive to be checked and sometimes "fixed" which required a restore of drive D.
I started pausing, and then stopping the cache before booting into another drive, and I disabled fast start on Windows 8.1, and the problems stopped completely for many months.
Yesterday, I forgot to stop the cache before rebooting into Windows 10, which is isolated totally on a separate drive, and has few programs installed, Comodo, a system information utility, a game plus benchmarks etc.
When I rebooted back to Windows 7, the drive D needed checking again, and there were errors,the first since Primocache had not been stopped prior to rebooting months ago.
Though I take regular backups of my drives, I decided to investigate where the corruption was following checkdisk "fixing" the errors. All the errors were in the section of the D drive that contained the same programs that were also on Windows 10, i.e. comodo. the system information utility, even the same game, all were corrupted, (and had been used). By restoring those pieces of software, all was OK. Those pieces of corrupted software represented only a small part of the physical drive. I also stress, these are totally separate copies of the software, all reinstalled individually on each operating system.
The only common denominator in my view is primocache. I therefore suggest that when rebooting into another operating system, primocache, which is not installed on neither of the other two operating systems, it is somehow resulting in the corruption. It would seem the only way that can happen is if Primocache is possibly still running in memory following the reboot?, perhaps booting from a shutdown would not have the same drastic consequences, but after spending all day yesterday rebuilding drive D investigating this, I do not want to go through the loop again so soon to test that theory. The copies of those programs were not corrupted on the other two systems.

Currently, as I am doing some beta testing on the game I mentioned, I have now left Primocache disabled, and after 8 or 9 reboots between systems all has been fine.
It may be this is a problem with my particular motherboard or bios not clearing the ram on a reboot, or something specific to my system, though in my view, the process of elimination indicates is a problem with Primo.
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Re: Drive corruption on a multi boot system

Post by Support »

Well, this is the issue called "offline modification" which is described in our help document when you use L2 cache. Please see
http://www.romexsoftware.com/en-us/prim ... cache.html
Though PrimoCache has the built-in verification mechanism as described above, it cannot prevent the case of "offline modification". "Offline modification" means that data in source disk or cache storage are modified when PrimoCache is not running. Given below is an example of "offline modification". Assume that you have a computer with dual-boot setup and you setup the level-2 cache for the volume N in one of the operating systems. If later you change the contents of the volume N, like copying, overwriting, deleting something to this volume, in another operating system, then volume N is offline modified. Because PrimoCache can do nothing when it is not running, it is the user's responsibility to avoid "offline modification".
Yozzer
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Re: Drive corruption on a multi boot system

Post by Yozzer »

Thanks for the quick response. I wrote I thought a detailed incident which made my problem clear, but it would seem I have failed.
1) The partition set aside and configured for L2 cash under Windows 7 is not seen in any of the other two operating systems as I would expect, so your analogy of drive being assigned a drive letter N is not valid.
2) As Primocache is not installed and running on Windows 10, the L2 cache should not have been written to, as no drive number is assigned to the partition that has been configured for the L2 cache. (It is seen under disk management, but not used or drive id assigned as I would expect)
3) The hard drive that was corrupted, was the drive seen by Windows 7 as drive D, which is cached by Primocache when I am using Windows 7.
4) The drive D under Window 7 that becomes corrupted, has not been used by Windows 10 at all, as I explained, Windows 10 is installed on its own drive, no programs installed on any other drive.
5) The software that was corrupted on drive D, were the same programs installed totally separately on the Windows 10 drive.
This means to me, that when the programs were accessed on the Windows 10 OS, somehow the cache WAS written to, even though THAT SHOULD NOT HAVE HAPPENED, as Primocache was not installed on Windows 10, and the partition used for cache not assigned for use.
I hope that makes the problem clearer. As I stated, when not using Primocache I can boot where I want to, use whatever programs I want to, with no corruption.
If you feel the cache is being written to legitimately as in used "off line", how? as the partition that is assigned as cache has no drive letter assignment. The assumption it is assigned a drive letter, which clearly would destroy the cache, is invalid in your response.
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Re: Drive corruption on a multi boot system

Post by Support »

"Offline modification" includes not only L2 cache but also target drives (here in your case it is drive D)
If possible, can you try to remove the drive letter D in Windows 10? This is to make drive D not seen by Windows 10 and to ensure that there will be no writes on drive D in Windows 10.
Yozzer
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Re: Drive corruption on a multi boot system

Post by Yozzer »

Thanks for the suggestion, and it is a possibility that would stop the corruption, though I cannot see why an OS would actually write to another drive it should not be using at all, specifically to duplicate copies of software used by another different OS.
I actually have a total of 9 drives on my system, (16 terabytes), and the only drive being corrupted is the one being cached by Primo after I boot into another system, imagine if I had them all cached! would I need to disable them when I have a dual boot system?
For the time being, I will simply continue with Primocache disabled until I have a couple of days spare to more fully investigate.
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