Date: Wed, 19 Feb 2014 15:06:53 -0500 From: Christian Campbell <dcamp@alumni.ufl.edu> To: freebsd-questions@freebsd.org Subject: System freezes up during long-running ZFS disk activity Message-ID: <CADbaceJ00rk8RFMwi-S-HLNBX673j2DGe6SngUcvYTFTd5KFxw@mail.gmail.com>
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I recently installed 9.2-RELEASE-p3 on a Dell Precision T5400. I'm using ZFS filesystem version: 5, ZFS storage pool version: features support (5000). The pool was imported from a previous 9.2 box on which it worked without issue. I don't know if my problem is ZFS-related, but my ZFS use is why I noticed it and I seem to be able to reproduce it reliably. Every so often, from minutes to hours, my computer will freeze up while ZFS has been busy. This happens during a resilver, a scrub, and a long-running process reading millions of files from the pool. When it freezes, all output and input freezes: tasks like zpool iostat -v 1 or top stop updating their output, whether on the console or an ssh terminal over Ethernet. Pressing keys does not garner a response.* Sometimes a freeze lasts minutes and then proceeds on its own. Sometimes it goes on for hours. An action that typically, but not always, jogs it is unplugging the USB keyboard -- the disk activity resumes immediately, and any queued keyboard input immediately plays out whether on the console or over ssh. Lastly, my ssh terminal (PuTTY) will stay connected for hours during a freeze-up, *i.e.* the TCP circuit is not closed or timed out, as opposed to closing pretty quickly after the server is powered off. In all cases, the system clock lags by the sum of the durations of the freezes. * During an initial resilver, I noticed that pressing a key such as Ctrl on the USB keyboard would jog it, but pressing Ctrl or other keys doesn't jog my process of long-running IO activity. But in all cases, even when unplugging and replugging the USB keyboard doesn't jog it, Ctrl-Alt-Del prompts an orderly shutdown. Debugging advise is very welcome! Thank you, Christian _____________________________________________________ 3425 SW 2nd Ave, #239 cell (352) 514-7411 Gainesville, FL 32607-2813 dcamp@alumni.ufl.edu On this perfect day / Nothing's standing in my way... -Hoku
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