Date: Tue, 20 Apr 2010 07:24:53 -0600 From: "Jason J. W. Williams" <jasonjwwilliams@gmail.com> To: Pawel Jakub Dawidek <pjd@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: ZFS behavior when device disappears Message-ID: <q2x3b949f091004200624me7a4504bjb73bd9b9ce35ad93@mail.gmail.com> In-Reply-To: <20100420064006.GE1728@garage.freebsd.pl> References: <r2l3b949f091004131639w68104646sb089332a84cfd607@mail.gmail.com> <20100420064006.GE1728@garage.freebsd.pl>
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Hi Pawel, Thank you very much for the response! Please forgive some of my questions, as I'm a bit unfamiliar with the FreeBSD port. What is the nature of the port? Is it something where each new version of ZFS is a from-scratch effort to some degree? Or is it a point where new ZFS versions are a matter of just making the newer features operational? -J On Tue, Apr 20, 2010 at 12:40 AM, Pawel Jakub Dawidek <pjd@freebsd.org> wro= te: > On Tue, Apr 13, 2010 at 05:39:30PM -0600, Jason J. W. Williams wrote: >> Hello, >> >> Currently, we're an OpenSolaris shop but with the way things are going >> over at Oracle/Sun we're starting to evaluate our options for keeping >> ZFS but moving off Solaris. One of my concerns is that FreeBSD is >> implementing ZFSv14 (ZFS itself is up to v23 I believe). For quite a >> long time, ZFS under Solaris had a real problem with the following >> scenario: >> >> * Hard drive starts to die >> * Controller and SCSI subsystem continue to retry an I/O rather than >> failing fast >> * Even if the I/O does fail fast ZFS doesn't really notice a spike in >> I/O failures and continues to use the drive. >> * Result: I/O on the zpool stalls completely while the I/Os continue >> to be tried against the drive. >> >> This got fixed in later revs of OpenSolaris by enhancements to ZFS and >> greater integration with the Fault Management Architecture (FMA) of >> Solaris...lots of I/Os failing on a drive get communicated to ZFS who >> then offlines the drive out of the pool. >> >> My question is, what is the situation in FreeBSD 8 with ZFS if that >> type of situation occurs? > > I believe FreeBSD does whatever OpenSolaris did for this version of ZFS. > There is nogoing work to bring v24 to FreeBSD. Basic functionality works > already, but a lot work is still needed. At some point I'll see what we > can do about it, because we don't have FMA in FreeBSD and we would need > to find another way to deal with it. I've limited time I can spend on > ZFS right now, so I'm making small steps, but I'm making good progress > too. > > -- > Pawel Jakub Dawidek =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 http://ww= w.wheelsystems.com > pjd@FreeBSD.org =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 http:= //www.FreeBSD.org > FreeBSD committer =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Am I Ev= il? Yes, I Am! >
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