Date: Wed, 19 Jan 2011 21:40:20 -0500 From: Dan Langille <dan@langille.org> To: John Hawkes-Reed <hirez@libeljournal.com> Cc: freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: ZFS - hot spares : automatic or not? Message-ID: <4D37A094.1090504@langille.org> In-Reply-To: <4D2C810E.2070007@libeljournal.com> References: <4D228F41.7040403@langille.org> <4D23504D.8060103@libeljournal.com> <4D2BD0A7.9060003@langille.org> <4D2C810E.2070007@libeljournal.com>
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On 1/11/2011 11:10 AM, John Hawkes-Reed wrote: > On 11/01/2011 03:38, Dan Langille wrote: >> On 1/4/2011 11:52 AM, John Hawkes-Reed wrote: >>> On 04/01/2011 03:08, Dan Langille wrote: >>>> Hello folks, >>>> >>>> I'm trying to discover if ZFS under FreeBSD will automatically pull >>>> in a >>>> hot spare if one is required. >>>> >>>> This raised the issue back in March 2010, and refers to a PR opened in >>>> May 2009 >>>> >>>> * http://lists.freebsd.org/pipermail/freebsd-fs/2010-March/007943.html >>>> * http://www.freebsd.org/cgi/query-pr.cgi?pr=134491 >>>> >>>> In turn, the PR refers to this March 2010 post referring to using devd >>>> to accomplish this task. >>>> >>>> http://lists.freebsd.org/pipermail/freebsd-stable/2010-March/055686.html >>>> >>>> >>>> Does the above represent the the current state? >>>> >>>> I ask because I just ordered two more HDD to use as spares. Whether >>>> they >>>> sit on the shelf or in the box is open to discussion. >>> >>> As far as our testing could discover, it's not automatic. >>> >>> I wrote some Ugly Perl that's called by devd when it spots a drive-fail >>> event, which seemed to DTRT when simulating a failure by pulling a >>> drive. >> >> Without such a script, what is the value in creating hot spares? > > We went through that loop in the office. > > We're used to the way the Netapps work here, where often one's first > notice of a failed disk is a visit from the courier with a replacement. > (I'm only half joking) > > In the end, writing enough perl to swap in the spare disk made much more > sense than paging the relevant admin on disk-fail and expecting them to > be able to type straight at 4AM. > > Our thinking is that having a hot spare allows us to do the physical > disk-swap in office hours, rather than (for instance) running in a > degraded state over a long weekend. > > If it's of interest, I'll see if I can share the code. I think this very much of interest. :) -- Dan Langille - http://langille.org/
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