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Re: standby on SAN ? or use internal storage

From: Arup Nanda <orarup_at_hotmail.com>
Date: Mon, 24 Mar 2003 10:43:38 -0500
Message-Id: <24765.322898@fatcity.com>


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Rahul,

The purpose of standby is to failover to it when the primary fails - = which could range from the CPU failure to SAN failure. Although modern = SANs are pretty robust, you account for the remote chance of failure by = building a standby. Placing the database on teh same SAN as the primary = does not really buy you any extra high availability feature, does it? = You have a single point of failure, the SAN.

So your Standby should use storage not in the same place as the primary. = However, using the standby server's internal disks could render your = filesystems inaccessible if the server fails. But in some hosts, this is = not a problem either; the SAs can mount the internal disks on another = machine and recover data - check with your SA. If this is not the case, = place the standby database on a different SAN.

So your preffered options are (in descending order)

(1) Primary Server - with two primary instances Primary SAN with the two primary databases Standby server=20
Standby SAN

(2) Primary Server - with two primary instances Primary SAN with the two primary databases Standby server=20
Internal storage on standby server

HTH. Arup

  list, i'm a bit confused on whether to put the standby DB on the SAN = storage or=20
  use the internal storage of the standby host !!!=20

  config a
  two instances on primary server, data-files on SAN, hot standby db = files on SAN too.
  standby instances for both primary on another machine

  config b
  both primary on SAN, standby db files on the itnernal storage of = standby machine

  any thoughts ?=20

  TIA
  Rahul

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<DIV><FONT face=3DArial size=3D2>Rahul,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>The purpose of standby is to failover =
to it when=20
the primary fails - which could range from the CPU failure to SAN = failure.=20
Although modern SANs are pretty robust, you account for the remote = chance of=20
failure by building a standby. Placing the database on teh same SAN as = the=20
primary does not really buy you any extra high availability feature, = does it?=20
You have a single point of failure, the SAN.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>So your Standby should use storage not =
in the same=20
place as the primary. However, using the standby server's internal disks = could=20
render&nbsp;your filesystems inaccessible if the server fails. But in = some=20
hosts, this is not a problem either; the SAs can mount the internal = disks on=20
another machine and recover data - check with your SA. If this is not = the case,=20
place the standby database on a different SAN.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>So your preffered options are (in =
descending=20
order)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>(1) Primary Server - with two primary=20
instances</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Primary SAN with the two primary=20
databases</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Standby server </FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Standby SAN</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>(2) Primary Server - with two primary =
instances
<DIV><FONT face=3DArial size=3D2>Primary SAN with the two primary=20
databases</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Standby server </FONT></DIV>
<DIV>Internal storage on standby server</DIV>
<DIV>&nbsp;</DIV>
<DIV>HTH.</DIV>
<DIV>&nbsp;</DIV>
<DIV>Arup</DIV></FONT></DIV>
<BLOCKQUOTE dir=3Dltr=20

style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">   <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>   <DIV=20
  style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: = black"><B>From:</B>=20
  <A title=3Drahul_at_infotech.co.id =
href=3D"mailto:rahul_at_infotech.co.id">Rahul</A>=20   </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A = title=3DORACLE-L_at_fatcity.com=20
  href=3D"mailto:ORACLE-L_at_fatcity.com">Multiple recipients of list = ORACLE-L</A>=20
  </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Monday, March 24, 2003 = 12:18=20
  AM</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> standby on SAN ? or = use internal=20
  storage</DIV>
  <DIV><BR></DIV>
  <DIV><FONT face=3DArial size=3D2>list, i'm a bit confused on whether = to put the=20
  standby DB on the SAN storage or </FONT></DIV>   <DIV><FONT face=3DArial size=3D2>use the internal storage of the = standby host !!!=20

  </FONT></DIV>
  <DIV>&nbsp;</DIV>
  <DIV><FONT face=3DArial size=3D2>config a</FONT></DIV>
  <DIV><FONT face=3DArial size=3D2>two instances on primary server, =
data-files on=20
  SAN, hot standby db files on SAN too.</FONT></DIV>   <DIV><FONT face=3DArial size=3D2>standby instances for both primary on = another=20
  machine</FONT></DIV>
  <DIV>&nbsp;</DIV>
  <DIV><FONT face=3DArial size=3D2>config b</FONT></DIV>
  <DIV><FONT face=3DArial size=3D2>both primary on SAN, standby db files =
on the=20
  itnernal storage of standby machine</FONT></DIV>
  <DIV>&nbsp;</DIV>
  <DIV><FONT face=3DArial size=3D2>any thoughts&nbsp; ? </FONT></DIV>
  <DIV>&nbsp;</DIV>
  <DIV><FONT face=3DArial size=3D2>TIA</FONT></DIV>
Received on Mon Mar 24 2003 - 09:43:38 CST

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