Date: Mon, 8 Dec 2014 02:30:26 -0700 From: Will Andrews <will@firepipe.net> To: Andriy Gapon <avg@freebsd.org> Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Re: ZFS weird issue... Message-ID: <CADBaqmj0gVDsrpU=zLhX8Ft-YFrOUM_XPeK%2BT1R76fHF310-wQ@mail.gmail.com> In-Reply-To: <5485681C.7010504@FreeBSD.org> References: <54825E70.20900@sorbs.net> <CADBaqmiPM7nSASjc80HpS1%2Bk62DwBnrr5DbwHQtWHyr7%2BwCE8A@mail.gmail.com> <54842CC5.2020604@sorbs.net> <CADBaqminLE%2BN1x9SYpuwf1LM9t7xQ8H=pj9RQW1vdECEThMH-A@mail.gmail.com> <5485681C.7010504@FreeBSD.org>
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On Monday, December 8, 2014, Andriy Gapon <avg@freebsd.org> wrote: > > BTW, Will, don't you have a patch that help the vdev phys path to stay > up-to-date? > I don't believe we have any patch for a situation where a member disappears altogether. Perhaps the best we could do for a situation like this would be to wipe the physical path in the label for a faulted device, to reduce confusion. But a device that's been either manually offlined or physically removed could come back and be resilvered. There are patches to provide physical paths through SES/SAF-TE/SGPIO which offer paths decidedly more physical than a device name. And to perform automatic replacement by physical path based on these. Not sure to what degree these have been integrated in the mainline. But this still requires the system to have an enclosure service of some sort. Fundamentally, documentation should make clear which /dev device names are logical and can be reordered due to configuration changes (including device departure and arrival events) or reboots. As opposed to those based on immutable properties of the device. In the case of ZFS, the ideal physical path identifies a slot, so ZFS can detect when a particular member is being replaced at its physical location by a new device. So using a device's serial number is a little too specific for the job. But a typical logical device name is not specific enough. --Will.
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