`<div dir="ltr"><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Mar 26, 2015 at 11:37 AM, Dan McDonald <span dir="ltr"><<a href="mailto:danmcd@omniti.com" target="_blank">danmcd@omniti.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">I mentioned earlier:<br>
<span class=""><br>
> I know Nexenta's done a LOT of improvements on this in illumos-nexenta. It might be time to upstream some of what they've done. I know it's a moving target (COMSTAR is not a well-written subsystem), so it may take some unravelling.<br>
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</span>I was looking at Nexenta's changes. They HAVE done a lot of work in these areas, and at some point someone needs to upstream them. Nexenta isn't under an obligation to upstream, just to publish, which they have.<br>
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I found one particular bug that MAY have manifested as your problem. Because 014's coming up, I can't get to it at the moment. If you've built kernel modules before, I can tell you where the fix should go and approximately what the fix is. You'd have to test it, however.<br>
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Sorry I can't be of more immediate assistance,<br>
Dan<br>
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</blockquote></div></div><div class="gmail_extra"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><font color="#888888"><br></font></blockquote></div><br></div><div class="gmail_extra">Hi Dan (just saw your latest reply as I was writing this),</div><div class="gmail_extra"><br></div><div class="gmail_extra">Thanks for all the time you've put into this. It certainly sounds like some of the Nexenta COMSTAR work might be useful. Is R151014 released yet? It looks like all the documentation is there but mentions Apr 3/2015. Is there any reason to believe that it might be fixed if there are no (or low amounts) of changes in COMSTAR for this release? (Sounds like it isn't, now that I've read your latest)</div><div class="gmail_extra"><br></div><div class="gmail_extra">It looks like I'll have to make do with lazy zeroed or thin provisioned disks of 10TB+ for my Veeam tests, if it doesn't cause another kernel panic. I'm hesitant to create these now during business hours (and I shouldn't be.. these are normal VM provisioning tasks on available storage!). In your estimation, would eager zero vs lazy zero vs thin provisioned vmdks make any difference with that WRITE_SAME code? The majority of my VMs use eager zeroed disks, but again, never to this size. </div><div class="gmail_extra"><br></div><div class="gmail_extra">If there is anything you need me to test (in R151014? or beyond?), it's easy enough for me to reproduce (I timed myself last night, it took me about 2 hours to gracefully shut/save all the VMs, cause the crash dump, and get the infrastructure back up). I should probably try it on Hyper-V as well when I get time, but I believe most of those are Dynamic (thin) instead of Fixed (eager zero) disks, and I don't believe Hyper-V has an equivalent to lazy zeroed. The Hyper-V environment runs our test VMs after all, and aren't as performance sensitive.</div><div class="gmail_extra"><br></div><div class="gmail_extra">If you can tell me where the fix should go, I can probably try it out, even though I haven't built any kernel modules before (though I'm sure there are enough resources for me to draw on). I'll start by making myself a build server on a VM. Is this <a href="http://wiki.illumos.org/display/illumos/How+To+Build+illumos">http://wiki.illumos.org/display/illumos/How+To+Build+illumos</a> still current?</div></div></div>
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