Date: Tue, 19 Apr 2016 17:33:22 -0400 From: Jon Radel <jon@radel.com> To: galtsev@kicp.uchicago.edu Cc: freebsd-questions@freebsd.org Subject: Re: Raid 1+0 Message-ID: <5716A422.6000707@radel.com> In-Reply-To: <44929.128.135.52.6.1461091476.squirrel@cosmo.uchicago.edu> References: <571533F4.8040406@bananmonarki.se> <57153E6B.6090200@gmail.com> <20160418210257.GB86917@neutralgood.org> <64031.128.135.52.6.1461017122.squirrel@cosmo.uchicago.edu> <441t61efpv.fsf@be-well.ilk.org> <13260.128.135.52.6.1461084740.squirrel@cosmo.uchicago.edu> <57166A7F.2030104@radel.com> <44929.128.135.52.6.1461091476.squirrel@cosmo.uchicago.edu>
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[-- Attachment #1 --] On 4/19/16 2:44 PM, Valeri Galtsev wrote: > My opinion that your conclusion that the drives having the same MTBF > (or similar lifespans) are likely to die simultaneously contradicts my > understanding of probability theory (or statistics basics). People > life expectancy in some country is 75 years. Likelyhood that two > _given_ people will die at age 40 is negligible. Even twin brothers > are unlikely to die during the same week or Month. This one is between > fundamental assumptions statistics is based on. Just my humble > opinion. Valeri You're confusing presence of correlation with a layman's "really, really likely." Of course the probability that two people of the same age will die in the same month is higher than the probability that two randomly selected people will die in the same month. Likelihood of death is not constant throughout life. Frankly I take the actuaries that suggest my insurance company up my life insurance premiums every 5 years waaaaaay more seriously than you. If you assume away all the interesting bits, your conclusions get pretty useless. Actually, people study this stuff. See, for example: http://biomedgerontology.oxfordjournals.org/content/53A/6/M441.full.pdf --Jon Radel jon@radel.com [-- Attachment #2 --] 0 *H 010 `He 0 *H 00 #SanzTgk!0 *H 0o1 0 USE10U AddTrust AB1&0$U AddTrust External TTP Network1"0 UAddTrust External CA Root0 141222000000Z 200530104838Z01 0 UGB10UGreater Manchester10USalford10U COMODO CA Limited1A0?U8COMODO SHA-256 Client Authentication and Secure Email CA0"0 *H 0 zSNpR V&IQZI`zQBy"aNv# J n=ٺ.CRC|2PȦOZϓ%{0dV*$3DiFK3@@:*S= a<UNv%!)|qvO_T{5R"=,0-1YR73i-C֥wgQ'뼥8v8ߌIs:2:=F:WtaP@?⟢! 00 U #0z4&&T$T0 U akᢠOg£ 0U 0U 0 0 U %0++0U 00U 0DU =0;09753http://crl.usertrust.com/AddTrustExternalCARoot.crl05+)0'0%+0http://ocsp.usertrust.com0 *H *nU:Uka+ #fjow^a } [jr AX&MX"cR6}Xޫ;cs{B#ʶM>K-ػBKiۦ74{:ǟO4ne6d)5ֱqC>2Svʆ4, Jؙ ␒ZBj#!eջ~ꌅ b:,Yř38z yJ&|00sT<}k `i 0 *H 01 0 UGB10UGreater Manchester10USalford10U COMODO CA Limited1A0?U8COMODO SHA-256 Client Authentication and Secure Email CA0 150330000000Z 180329235959Z01 0 UUS10 U221501 0 UVA10U Springfield10U 6917 Ridgeway Dr.10U Jon T. Radel1200U )Issued through Jon T. Radel E-PKI Manager1 0 U Corporate Secure Email10U Jon Radel1 0 *H jon@radel.com0"0 *H 0 aЩ@@g3eGރ͛; d#>q7&Hf :3vL" jV#Xݷ>U-H[$SUڻ{Ϝ,z¶IchO=rcyr n v.Vh7k;%ueYuӬnz 6!| !Aȡ+,u+ CAպF-un#vjUJWnk%j] 2JPkl 00 U #0akᢠOg£ 0 U E|GDp/ʚB0U 0 U 0 0 U %0++0FU ?0=0; +10+0)+ https://secure.comodo.net/CPS0]U V0T0RPNLhttp://crl.comodoca.com/COMODOSHA256ClientAuthenticationandSecureEmailCA.crl0+00X+0Lhttp://crt.comodoca.com/COMODOSHA256ClientAuthenticationandSecureEmailCA.crt0$+0http://ocsp.comodoca.com0U 0 jon@radel.com0 *H KS `?H_D`8G߿ VbĘ<tB-Ӈї|{'Ũݹg0Gp$%F(;*MO*gt$@ t6,?0|#ăz,&! {j2i[%b7ߪP+9G㲍["y<?8rZ'[UR6%L̤ w"=:L~Ƨ^jf36 OP1.}(e1A0=001 0 UGB10UGreater Manchester10USalford10U COMODO CA Limited1A0?U8COMODO SHA-256 Client Authentication and Secure Email CAsT<}k `i 0 `He a0 *H 1 *H 0 *H 1 160419213322Z0/ *H 1" AOu1xM?] J'H^3s 0l *H 1_0]0 `He*0 `He0 *H 0*H 0 *H @0+0 *H (0 +71001 0 UGB10UGreater Manchester10USalford10U COMODO CA Limited1A0?U8COMODO SHA-256 Client Authentication and Secure Email CAsT<}k `i 0 *H 101 0 UGB10UGreater Manchester10USalford10U COMODO CA Limited1A0?U8COMODO SHA-256 Client Authentication and Secure Email CAsT<}k `i 0 *H ơIm5!B 15nkc-}ˡZDnS.\pI;d[EX *~@<HV$y]NJGC5R| EV.. A rD]n9Nx="Pw+z{S6>HPfC.L^" 7 F|C2- i]쇞Hl0Uۃ%`ŠCV3XԳpz/F -AkKRl"9,[ |E%{E
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