[31578] in North American Network Operators' Group
RE: availability and resiliency
daemon@ATHENA.MIT.EDU (Roeland M.J. Meyer)
Fri Sep 29 14:33:31 2000
Message-ID: <1148622BC878D411971F0060082B042C374B@hawk.lvrmr.mhsc.com>
From: "Roeland M.J. Meyer" <rmeyer@MHSC.com>
To: Leo Nelson <lnelson@axient.com>, "'nop@alt.net'" <nop@alt.net>,
Andrew Bangs <andrewb@demon.net>
Cc: nanog@merit.edu
Date: Fri, 29 Sep 2000 11:30:12 -0700
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It refers to the percent uptime of a host or site. 99% is two "9"'s
(2x9?) and 99.9% is three nines. Getting a single host to meet more =
than
three nines (99.9%) can be a challenge ( <8.76 hours outage, per year),
but can be more easily met with multiple hosts in a site. Four nines
(99.99% uptime, <0.88 hours annual downtime) is extremely difficult for
a single host, less difficult for internal data centers, and (given =
lots
of $$$) a bit easier for a internet site (using multiply redundant
hosts). Five nines (99.999%, <5.26 annual minutes down) is almost
impossible for a single affordable host to meet. This is where we enter
the world of High-Availability (H-A) systems. These are usually high
transaction flow critical systems and are found in large corps, telcos,
and reliable internet sites. At this time, only governments are willing
to part with the required cash to build systems meeting six nines
(99.9999%, <0.53 minutes annual downtime), or better (NASA, NORAD, US
Space Command, etc). Usually, this is done using multiple site
redundancy.
=A0
Hosts meeting three nines, or better, typically have redundant power
supplies and integrated UPS, bootable RAID for the OS, redundant NICs,
and=A0SMP CPU configurations.
-----Original Message-----
From: Leo Nelson [mailto:lnelson@axient.com]
Sent: Friday, September 29, 2000 10:08 AM
To: 'nop@alt.net'; Andrew Bangs
Cc: nanog@merit.edu
Subject: RE: availability and resiliency
Pardon my ignorance, but what the heck does a "9" refer too? Is it a
UPS, rack, floor space, circuit...=20
Thanks in advance=20
-leo=20
-----Original Message-----=20
From: Lionel Lauer [ mailto:longword@newsguy.com]=20
Sent: Friday, September 29, 2000 10:54 AM=20
To: Andrew Bangs=20
Cc: nanog@merit.edu=20
Subject: Re: availability and resiliency=20
On Fri, 29 Sep 2000 17:39:04 +0100, Andrew Bangs <andrewb@demon.net>=20
wrote:=20
>=20
>On Thu, Sep 28, 2000 at 02:39:40PM -0600, Irwin Lazar wrote:=20
>> Hi all,=20
>> Does anyone know if a template exists for what it takes to provide 5
9's of=20
>> availability, 4 9's etc.for Internet data centers?=A0 Specifically =
I'm
looking=20
>> for something that would say "if you want 5 9's of availability,
here's what=20
>> you need to do", and so on.=20
>=20
>For 5 9s you need:=20
>=20
>1) Lots of money=20
>2) Lots of clue=20
>3) Lots of luck=20
>4) Lots of balls=20
>=20
>You can do 4 9s with any 3 of the above.=20
Too true.=20
But you forgot to include 'halfway-clued management' - without that you =
haven't got a hope in hell of even getting three 9's. ;)=20
--=20
=A0=A0 W=A0=A0=A0=A0=A0=A0=A0=A0=A0=20
=A0. | ,. w ,=A0=A0 "Some people are alive only because=20
=A0 \|/=A0 \|/=A0=A0=A0=A0 it is illegal to kill them."=A0=A0=A0 Perna =
condita delenda est
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<TITLE>RE: availability and resiliency</TITLE>
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<DIV><SPAN class=3D816460118-29092000><FONT face=3DArial =
color=3D#0000ff size=3D2>It=20
refers to the percent uptime of a host or site. 99% is two "9"'s (2x9?) =
and=20
99.9% is three nines. Getting a single host to meet more than three =
nines=20
(99.9%) can be a challenge ( <8.76 hours outage, per year), but can =
be more=20
easily met with multiple hosts in a site. Four nines (99.99% uptime, =
<0.88=20
hours annual downtime) is extremely difficult for a single host, less =
difficult=20
for internal data centers, and (given lots of $$$) a bit easier for a =
internet=20
site (using multiply redundant hosts). Five nines (99.999%, <5.26 =
annual=20
minutes down) is almost impossible for a single affordable host to =
meet. This is=20
where we enter the world of High-Availability (H-A) systems. These are =
usually=20
high transaction flow critical systems and are found in large corps, =
telcos, and=20
reliable internet sites. At this time, only governments are willing to =
part with=20
the required cash to build systems meeting six nines (99.9999%, =
<0.53 minutes=20
annual downtime), or better (NASA, NORAD, US Space Command, etc). =
Usually, this=20
is done using multiple site redundancy.</FONT></SPAN></DIV>
<DIV><SPAN class=3D816460118-29092000><FONT face=3DArial =
color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D816460118-29092000><FONT face=3DArial =
color=3D#0000ff size=3D2>Hosts=20
meeting three nines, or better, typically have redundant power supplies =
and=20
integrated UPS, bootable RAID for the OS, redundant NICs, and SMP =
CPU=20
configurations.</FONT></SPAN></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px =
solid; MARGIN-RIGHT: 0px">
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> Leo Nelson=20
[mailto:lnelson@axient.com]<BR><B>Sent:</B> Friday, September 29, =
2000 10:08=20
AM<BR><B>To:</B> 'nop@alt.net'; Andrew Bangs<BR><B>Cc:</B>=20
nanog@merit.edu<BR><B>Subject:</B> RE: availability and=20
resiliency<BR><BR></FONT></DIV>
<P><FONT size=3D2>Pardon my ignorance, but what the heck does a "9" =
refer too?=20
Is it a UPS, rack, floor space, circuit...</FONT> </P>
<P><FONT size=3D2>Thanks in advance</FONT> <BR><FONT =
size=3D2>-leo</FONT> </P>
<P><FONT size=3D2>-----Original Message-----</FONT> <BR><FONT =
size=3D2>From:=20
Lionel Lauer [<A=20
=
href=3D"mailto:longword@newsguy.com">mailto:longword@newsguy.com</A>]</F=
ONT>=20
<BR><FONT size=3D2>Sent: Friday, September 29, 2000 10:54 AM</FONT> =
<BR><FONT=20
size=3D2>To: Andrew Bangs</FONT> <BR><FONT size=3D2>Cc: =
nanog@merit.edu</FONT>=20
<BR><FONT size=3D2>Subject: Re: availability and resiliency</FONT> =
</P><BR><BR>
<P><FONT size=3D2>On Fri, 29 Sep 2000 17:39:04 +0100, Andrew Bangs=20
<andrewb@demon.net></FONT> <BR><FONT size=3D2>wrote:</FONT> =
</P>
<P><FONT size=3D2>></FONT> <BR><FONT size=3D2>>On Thu, Sep 28, =
2000 at=20
02:39:40PM -0600, Irwin Lazar wrote:</FONT> <BR><FONT =
size=3D2>>> Hi=20
all,</FONT> <BR><FONT size=3D2>>> Does anyone know if a =
template exists=20
for what it takes to provide 5 9's of</FONT> <BR><FONT =
size=3D2>>>=20
availability, 4 9's etc.for Internet data centers? Specifically =
I'm=20
looking</FONT> <BR><FONT size=3D2>>> for something that would =
say "if you=20
want 5 9's of availability, here's what</FONT> <BR><FONT =
size=3D2>>> you=20
need to do", and so on.</FONT> <BR><FONT size=3D2>></FONT> =
<BR><FONT=20
size=3D2>>For 5 9s you need:</FONT> <BR><FONT size=3D2>></FONT> =
<BR><FONT=20
size=3D2>>1) Lots of money</FONT> <BR><FONT size=3D2>>2) Lots =
of clue</FONT>=20
<BR><FONT size=3D2>>3) Lots of luck</FONT> <BR><FONT =
size=3D2>>4) Lots of=20
balls</FONT> <BR><FONT size=3D2>></FONT> <BR><FONT =
size=3D2>>You can do 4 9s=20
with any 3 of the above.</FONT> </P>
<P><FONT size=3D2>Too true.</FONT> </P>
<P><FONT size=3D2>But you forgot to include 'halfway-clued =
management' - without=20
that you</FONT> <BR><FONT size=3D2>haven't got a hope in hell of even =
getting=20
three 9's. ;)</FONT> </P>
<P><FONT size=3D2>-- </FONT><BR><FONT size=3D2> =20
W =
</FONT><BR><FONT=20
size=3D2> . | ,. w , "Some people are alive only =
because</FONT>=20
<BR><FONT size=3D2> \|/ \|/ it is =
illegal to=20
kill them." Perna condita delenda est</FONT> =
<BR><FONT=20
=
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