Date: Thu, 21 Sep 2017 12:33:24 +0100 From: Karl Pielorz <kpielorz_lst@tdx.co.uk> To: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> Cc: freebsd-xen@freebsd.org Subject: Re: Storage 'failover' largely kills FreeBSD 10.x under XenServer? Message-ID: <1913BD3E6623F2384770C39E@[10.12.30.106]> In-Reply-To: <201709201815.v8KIF7Gi089958@pdx.rh.CN85.dnsmgr.net> References: <201709201815.v8KIF7Gi089958@pdx.rh.CN85.dnsmgr.net>
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--On 20 September 2017 11:15 -0700 "Rodney W. Grimes" <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> wrote: > As you found one of these let me point out the pair of them: > kern.cam.ada.default_timeout: 30 > kern.cam.ada.retry_count: 4 Adjusting these doesn't seem to make any difference at all. All the VM's (the control one, running defaults) - and the 3 others (one running longer timeouts, one running more retries - and one running both longer timeouts and retries) - all start throwing I/O errors on the console at the same time (e.g. regardless if the timeout is set to default 30 seconds, or extended out to 120) - I/O errors pop up at the same time. It looks like they're either ignored, or 'not applicable' for this scenario. Of particular concern is - if I adjust the 'timeout' value from 30 to 100 seconds, and 'time' how long the first I/O error takes to appear on the console, it's still ~30 seconds. I'm going to re-setup the test VM's - with a 'stable' boot disk (that won't go away during the switch) to give me something to log to - I should be able to work out the timings involved then, to see if the first I/O error really does surface after 30 seconds, or not. If the timeout is set to, say 100 seconds - I shouldn't see any console errors until then, should I? - unless some other part of the storage stack is still timing out first at 30 seconds? -Karl
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