Date: Sun, 23 Mar 2014 13:45:37 -0500 From: Karl Denninger <karl@denninger.net> To: freebsd-stable@freebsd.org Subject: Re: ZFS cautions (pool flag additions committed) Message-ID: <532F2BD1.4080606@denninger.net> In-Reply-To: <532F2B1B.5090702@egr.msu.edu> References: <532F1ED8.8010004@denninger.net> <532F2B1B.5090702@egr.msu.edu>
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[-- Attachment #1 --] On 3/23/2014 1:42 PM, Adam McDougall wrote: > On 03/23/2014 13:50, Karl Denninger wrote: >> When ZFS code imports are brought forward that add feature flags there >> is a potential time bomb for existing users in that creation of a new >> pool becomes non-revertible (except read-only!) with regard to mounting >> on older revisions of the code. >> >> The same thing happens if you do a "zpool upgrade" of course, but at >> least that's an explicit act. You might not realize that you're at risk >> on a pool create, however, unless you **carefully** scrutinize the flags >> that were on the last version compared against the current one. >> >> The primary "gotcha" here occurs if you don't upgrade your emergency >> boot media and for some reason you need to boot from a CD or USB key -- >> you can be left SEVERELY screwed, and since -RELEASE is typically not >> rebuilt when this happens if you don't have a second machine laying >> around on which you can build a RELEASE image.... >> >> I've caught this twice now since 10.0-RELEASE shipped and, while I >> haven't been bit by it, it serves as a caution because eventually >> someone tracking -STABLE is going to get badly hurt and be left with an >> unrepairable system. IMHO there should be some sort of notice on the >> list when new zpool feature flags show up so you're fairly warned that >> building a new emergency boot media copy is required if you intend to >> track -STABLE on a continuing basis. >> > I understand your point, but you can also get snapshot isos built pretty > regulary, so there should be no need to build your own in an emergency: > > ftp://ftp.freebsd.org/pub/FreeBSD/snapshots/ISO-IMAGES/ > > If weekly is not good enough, you can get daily: > > https://pub.allbsd.org/FreeBSD-snapshots/ It just seems to have become a more-frequent thing of late and I thought people ought to pay attention to it. You're definitely going to be unhappy if you wind up with recovery media that won't mount your disks! -- -- Karl karl@denninger.net [-- Attachment #2 --] 0 *H 01 0 + 0 *H O0K030 *H 01 0 UUS10UFlorida10U Niceville10U Cuda Systems LLC1 0UCuda Systems LLC CA1/0- *H customer-service@cudasystems.net0 130824190344Z 180823190344Z0[1 0 UUS10UFlorida10UKarl Denninger1!0 *H karl@denninger.net0"0 *H 0 bi՞] MNԿawx?`)'ҴcWgR@BlWh+ u}ApdCF JVй~FOL }EW^bچYp3K& ׂ(R lxڝ.xz?6 &nsJ +1v9 v/( kqĪp[vjcK%fϻe?iq]z lyzFO'ppdX//Lw(3 JI A*S#՟H[f|CGqJKoo y.oEuOw$ /섀$삻J9b|A P~8]D1YI<"""Y^T2iQ2 b yH)] Ƶ0y$ _N 6XqMC 9 XgώjGTP"#nˋ"Bk1 00 U 0 0 `HB0 U 0, `HB OpenSSL Generated Certificate0 U |8 ˴d[20 U #0]Af4 U3x&^"408 `HB+)https://cudasystems.net:11443/revoked.crl0 *H gBwH] j\x`( &gW32"Uf^. ^Iϱ k!DQA g{(w /)\N'[ oRW @C HO>)XrTNɘ!u`xt5(=f\-l3<@C6mnhv##1ŃbH͍_Nq aʷ?rk$^9TIa!kh,D -ct1 0001 0 UUS10UFlorida10U Niceville10U Cuda Systems LLC1 0UCuda Systems LLC CA1/0- *H customer-service@cudasystems.net0 + ;0 *H 1 *H 0 *H 1 140323184537Z0# *H 1-J RF䬚|0l *H 1_0]0 `He*0 `He0 *H 0*H 0 *H @0+0 *H (0 +71001 0 UUS10UFlorida10U Niceville10U Cuda Systems LLC1 0UCuda Systems LLC CA1/0- *H customer-service@cudasystems.net0 *H 101 0 UUS10UFlorida10U Niceville10U Cuda Systems LLC1 0UCuda Systems LLC CA1/0- *H customer-service@cudasystems.net0 *H }=9e<a߁ aBP75}l IG[w:C®:(R*b?Q %9g c9z\lmΠ%=D4qyYPj!j[˘L B $R}6a q6Vѻ2 2hwPǩˮ꣡7g[%+@ ,Mu~n@*37l仁 3 7{~ ~+'%VV"{8--ttDB}G{ R &v6̸| T.Riߴ1RϦpGzZ{LymиLƳ[S= # a'aH o +_ Oc>?C"܁A4{WPct /$,:`j߇n$Z pUOCZ GOscZA" GfӞa S="4Dƪ? Sں8d
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