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Home -> Community -> Mailing Lists -> Oracle-L -> RE: RAC or Oracle Fail Safe
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Hi Rajesh,=20
Thanks for the detailed reply and I really appreciate that. Certain =
clarifications.
1. With reference to what you said about using both =the nodes, you meant that we can install another database (lets say for = reporting purpose) or/and also 9iAS on one node and our main production = database on the other
2. Incase of OFS, the database service fails over from = one node to the other, and then it starts, but it is automatic, right? 3. When you talk about Resources and that they can't =be shared, you are not referring to the shared storage vault (we are = using DAS - Direct Attached Storage) because that has to be at least = available to both the servers. And when the database fails over from one = server to the other, and it starts its services on the other server, = then the obviously that other server will make use of the DAS on which = reside our datafiles.
4. RAC costs roughly 20k$ per CPU and it doesn't come = bundled with Oracle 9i License? (For confirmation purposes)=20 5. From various mails I gather that OFS is basically a =safe bet, if the hardware supporting is good. And if, God-forbid, one = server goes down then the only time lapse is the time it takes to start = the services on the other server.
6. The transactions taking place at the time when main =server goes down will be lost, I mean it will give a feeling of hung = database or some other error.
RAC can have Active-Active or Active-Passive combination for two nodes. = While OFS can't give you Active-Active combination of two nodes. = Basically a resource sharing is not possible in Oracle Fail safe so one = resource can be used by only one node at one point of time. ( Resource = means Hard Disk Space, Oracle Service, Listener etc).
RAC can give "Transparent Application Failover" TAF which is out of = consideration in OFS.
In case of node failure on RAC System, the user will just need to = attempt relogin and he will be connected _immediately_ to another = surviving instance ( If tnsnames.ora is configured properly). While = there is a significant amount of delay in case of OFS, the Database = service has to failover from one node to another node and this may take = it's own _sweet_ amount of time based on amount and type of activity = being performed on the database.
Of course both the systems are screwed when your (shared) storage system = is down ;-)
Lastly why would someone want to use only 1 out of 2 nodes when it is = possible to use both the nodes? One possible answer is that, on one node = you configure One server (say 9iAS) and on another node you configure = database. Then under normal condition they will run on their respective = nodes and when one fails they would switch-over to the surviving node. = So your performance may suffer for the time during which any node is = down.
So you are the best judge to decide now ;-)
Just my .2 c
Regards,
Rajesh
-----Original Message-----
HREF=3D"mailto:ml-errors_at_fatcity.com">mailto:ml-errors_at_fatcity.com] On =
Behalf Of Hussain Ahmed Qadri
Sent: Wednesday, July 16, 2003 8:44 PM
To: Multiple recipients of list ORACLE-L Subject: RAC or Oracle Fail Safe
Hello all,
We have setup a Microsoft Cluster Server (MSCS) cluster, with two nodes, = using W2K, and now are in the process of deploying Oracle 9i on it. For = the purpose of high availability (HA), we are deliberating on setting up = either RAC or Oracle Fail Safe. The confusion is over the fact that if = we get HA with oracle Fail Safe, i.e. if one node is down due to any = problem, then the other takes over, then can we do without RAC? Which of these two is more transparent to the user, i.e. which will take = less time to shift the load from one node (server) to the other node? Can any one explain the benefits of using RAC over Oracle Fail Safe, or = vice versa.
Regards,
Hussain
DBA SKMCH&RC
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Hussain Ahmed Qadri INET: hussain_at_skm.org.pk Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). 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Certain = clarifications.<o:p></o:p></span></font></span></p> <p class=3DMsoNormal = style=3D'margin-left:.75in;text-indent:-.5in;mso-list:l0 level1 lfo2; tab-stops:list .75in'><![if !supportLists]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>1.<font size=3D1 face=3D"Times New = Roman"><span style=3D'font:7.0pt "Times New = Roman"'>  = ; </span></font></span></font></span><![endif]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>With reference to what you said about using = both the nodes, you meant that we can install another database (lets say for = reporting purpose) or/and also 9iAS on one node and our main production database on the = other<o:p></o:p></span></font></span></p> <p class=3DMsoNormal = style=3D'margin-left:.75in;text-indent:-.5in;mso-list:l0 level1 lfo2; tab-stops:list .75in'><![if !supportLists]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>2.<font size=3D1 face=3D"Times New = Roman"><span style=3D'font:7.0pt "Times New = Roman"'>  = ; </span></font></span></font></span><![endif]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>Incase of OFS, the database service fails over = from one node to the other, and then it starts, but it is automatic, = right?<o:p></o:p></span></font></span></p> <p class=3DMsoNormal = style=3D'margin-left:.75in;text-indent:-.5in;mso-list:l0 level1 lfo2; tab-stops:list .75in'><![if !supportLists]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>3.<font size=3D1 face=3D"Times New = Roman"><span style=3D'font:7.0pt "Times New = Roman"'>  = ; </span></font></span></font></span><![endif]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>When you talk about Resources and that they = can’t be shared, you are not referring to the shared storage vault (we are using = DAS – Direct Attached Storage) because that has to be at least available to = both the servers. And when the database fails over from one server to the other, = and it starts its services on the other server, then the obviously that other = server will make use of the DAS on which reside our = datafiles.<o:p></o:p></span></font></span></p> <p class=3DMsoNormal = style=3D'margin-left:.75in;text-indent:-.5in;mso-list:l0 level1 lfo2; tab-stops:list .75in'><![if !supportLists]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>4.<font size=3D1 face=3D"Times New = Roman"><span style=3D'font:7.0pt "Times New = Roman"'>  = ; </span></font></span></font></span><![endif]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>RAC costs roughly 20k$ per CPU and it = doesn’t come bundled with Oracle 9i License? (For confirmation purposes) = <o:p></o:p></span></font></span></p> <p class=3DMsoNormal = style=3D'margin-left:.75in;text-indent:-.5in;mso-list:l0 level1 lfo2; tab-stops:list .75in'><![if !supportLists]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>5.<font size=3D1 face=3D"Times New = Roman"><span style=3D'font:7.0pt "Times New = Roman"'>  = ; </span></font></span></font></span><![endif]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>From various mails I gather that OFS is = basically a safe bet, if the hardware supporting is good. And if, God-forbid, one = server goes down then the only time lapse is the time it takes to start the = services on the other server.<o:p></o:p></span></font></span></p> <p class=3DMsoNormal = style=3D'margin-left:.75in;text-indent:-.5in;mso-list:l0 level1 lfo2; tab-stops:list .75in'><![if !supportLists]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>6.<font size=3D1 face=3D"Times New = Roman"><span style=3D'font:7.0pt "Times New = Roman"'>  = ; </span></font></span></font></span><![endif]><span = class=3DEmailStyle19><font size=3D2 color=3Dnavy face=3DArial><span = style=3D'font-size:10.0pt;mso-bidi-font-size: 12.0pt;font-family:Arial'>The transactions taking place at the time when = main server goes down will be lost, I mean it will give a feeling of hung = database or some other error.<o:p></o:p></span></font></span></p> <p class=3DMsoNormal><span class=3DEmailStyle19><font size=3D2 = color=3Dnavy face=3DArial><span style=3D'font-size:10.0pt;mso-bidi-font-size:12.0pt;font-family:Arial'><!= [if = !supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p> <p class=3DMsoNormal><span class=3DEmailStyle19><font size=3D2 = color=3Dnavy face=3DArial><span style=3D'font-size:10.0pt;mso-bidi-font-size:12.0pt;font-family:Arial'>Th= anks in advance, and waiting for your reply.<o:p></o:p></span></font></span></p> <p class=3DMsoNormal><span class=3DEmailStyle19><font size=3D2 = color=3Dnavy face=3DArial><span style=3D'font-size:10.0pt;mso-bidi-font-size:12.0pt;font-family:Arial'><!= [if = !supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p> <p class=3DMsoNormal><span class=3DEmailStyle19><font size=3D2 = color=3Dnavy face=3DArial><span style=3D'font-size:10.0pt;mso-bidi-font-size:12.0pt;font-family:Arial'>Re= gards,<o:p></o:p></span></font></span></p> <p class=3DMsoNormal><span class=3DEmailStyle19><font size=3D2 = color=3Dnavy face=3DArial><span style=3D'font-size:10.0pt;mso-bidi-font-size:12.0pt;font-family:Arial'><!= [if = !supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p> <p class=3DMsoNormal><span class=3DEmailStyle19><font size=3D2 = color=3Dnavy face=3DArial><span style=3D'font-size:10.0pt;mso-bidi-font-size:12.0pt;font-family:Arial'>Hu= ssain<o:p></o:p></span></font></span></p> <p class=3DMsoNormal><span class=3DEmailStyle19><font size=3D2 = color=3Dnavy face=3DArial><span style=3D'font-size:10.0pt;mso-bidi-font-size:12.0pt;font-family:Arial'><!= [if = !supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p> <p class=3DMsoNormal><span class=3DEmailStyle19><font size=3D2 = color=3Dnavy face=3DArial><span style=3D'font-size:10.0pt;mso-bidi-font-size:12.0pt;font-family:Arial'><!= [if = !supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p> <p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 = color=3Dblack face=3DTahoma><span = style=3D'font-size:10.0pt;font-family:Tahoma;color:black'>-----Original Message-----<br> <b><span style=3D'font-weight:bold'>From:</span></b> RAJESH DAYAL = [mailto:rajesh_at_ohitelecom.com]<br> <b><span style=3D'font-weight:bold'>Sent:</span></b> Thursday, July 17, = 2003 12:30 PM<br> <b><span style=3D'font-weight:bold'>To:</span></b> Multiple recipients = of list ORACLE-L<br> <b><span style=3D'font-weight:bold'>Subject:</span></b> RE: RAC or = Oracle Fail Safe</span></font><font color=3Dnavy><span = style=3D'color:navy;mso-color-alt:windowtext'><o:p></o:p></span></font></= p> <p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D3 = color=3Dnavy face=3D"Times New Roman"><span = style=3D'font-size:12.0pt;color:navy'><![if = !supportEmptyParas]> <![endif]></span></font><font color=3Dnavy><span = style=3D'color:navy;mso-color-alt:windowtext'><o:p></o:p></span></font></= p> <p style=3D'margin-left:.5in'><font size=3D2 color=3Dblack face=3D"Times = New Roman"><span style=3D'font-size:10.0pt;color:black'>Hi Hussain !<br> <br> RAC can have Active-Active or Active-Passive combination for two nodes. = While OFS can't give you Active-Active combination of two nodes. Basically a = resource sharing is not possible in Oracle Fail safe so one resource can be used = by only one node at one point of time. ( Resource means Hard Disk Space, Oracle Service, Listener etc).<br> <br> RAC can give "Transparent Application Failover" TAF which is = out of consideration in OFS.<br> <br> In case of node failure on RAC System, the user will just need to = attempt relogin and he will be connected _immediately_ to another surviving = instance ( If tnsnames.ora is configured properly). While there is a significant = amount of delay in case of OFS, the Database service has to failover from one node = to another node and this may take it's own _sweet_ amount of time based on = amount and type of activity being performed on the database.<br> <br> Of course both the systems are screwed when your (shared) storage system = is down ;-)<br> <br> Lastly why would someone want to use only 1 out of 2 nodes when it is = possible to use both the nodes? One possible answer is that, on one node you = configure One server (say 9iAS) and on another node you configure database. Then = under normal condition they will run on their respective nodes and when one = fails they would switch-over to the surviving node. So your performance may = suffer for the time during which any node is down.<br> <br> So you are the best judge to decide now ;-)<br> <br> Just my .2 c<br> <br> Regards,<br> Rajesh<br> <br> <br> -----Original Message-----<br> HREF=3D"mailto:ml-errors_at_fatcity.com">mailto:ml-errors_at_fatci= ty.com] On Behalf Of Hussain Ahmed Qadri<br> Sent: Wednesday, July 16, 2003 8:44 PM<br> To: Multiple recipients of list ORACLE-L<br> Subject: RAC or Oracle Fail = Safe<br> <br> Hello all,<br> <br> We have setup a Microsoft Cluster Server (MSCS) cluster, with two nodes, = using W2K, and now are in the process of deploying Oracle 9i on it. For the = purpose of high availability (HA), we are deliberating on setting up either RAC = or Oracle Fail Safe. The confusion is over the fact that if we get HA with = oracle Fail Safe, i.e. if one node is down due to any problem, then the other = takes over, then can we do without RAC?<br> Which of these two is more transparent to the user, i.e. which will take = less time to shift the load from one node (server) to the other node?<br> Can any one explain the benefits of using RAC over Oracle Fail Safe, or = vice versa.<br> <br> Regards,<br> <br> Hussain<br> <br> DBA SKMCH&RC<br> <br> --<br> Please see the official ORACLE-L FAQ: <a = href=3D"http://www.orafaq.net">http://www.orafaq.net</a><br> --<br> Author: Hussain Ahmed Qadri<br> INET: hussain_at_skm.org.pk<br> <br> Fat City Network Services -- 858-538-5051 <a href=3D"http://www.fatcity.com">http://www.fatcity.com</a><br> San Diego, California -- = Mailing list and web hosting services<br> ---------------------------------------------------------------------<br>=Received on Sat Jul 19 2003 - 01:47:09 CDT
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