Replication and HDR
We are looking at implementing replication between 2 of our servers, a primary in Ft. Lauderdale and the secondary in L.A., possibly using Informix's High Availability Data Replication (HDR) tool. Our questions are these: 1. The Informix manuals state that the hardware and OS must be identical for the primary and secondary server. How much flexibility is there on this? The Ft. Lauderdale machine is an IBM RS/6000 J30 and the L.A. machine is an IBM RS/6000 F30. Our Ft. Lauderdale machine has 4 CPU's and the L.A. machine has 1. We have AIX 4.3.2 running on our primary machine in Ft. Lauderdale and AIX 4.3.1 running on the secondary machine in L.A. Our Ft. Lauderdale machine has 512MB of memory and the L.A. machine has 256MB. It's been recommended that we sync the AIX versions, but I haven't gotten a definitive answer on the hardware. Do any of these situations require changes? It's not a great undertaking to upgrade the L.A. machine to 4.3.2. 2. We've found some comments on the web regarding the Informix version to use for replication. Most of those of a positive nature recommend using v7.31uc4, or at least v7.31uc3. We're leaning toward syncing them at v7.31uc4, charmed with the notion that the latest should be the greatest. 3. Can HDR be implemented using buffered logging instead of unbuffered logging? The production databases on both these machines currently use buffered logging? Are there disadvantages to doing that? 4. If we're configuring for a primary/secondary scenario with the secondary to serve as a hot backup, what would be the preferred method of transfer? Asynchronous or synchronous? 5. Also, the dbspaces, logical logs, physical log, and config files are virtually the same, needing only some minor tweeking to sync them up. Does HDR sound like a decent solution for our requirements? We need a hot backup server that can stand in and handle production processes in the case of failure of the primary server in Ft. Lauderdale, with the least amount of impact to the primary production system. No writes are to take place on the secondary, unless the primary were to fail. The machines can already talk to each other through the network. Thanks Much, Greg Sent via Deja.com http://www.deja.com/ Before you buy.
I have used HDR cross-country over a dedicated wan line with some success. the systems were both e3000 Sun Machines running the same patch level of the OS, and the same version of Informix 7.24.UC6. The system configurations differed as far as the number of cpu's and amount of ram but that was not a problem. We used asynchronous for performance reasons but still suffered at times when the wan line load was high. I suspect a bigger pipe would have alleviated most of those problems. ----- Original Message ----- From: <gresmi@yahoo.com> To: <comp.databases.informix@list.deja.com> Sent: Tuesday, November 30, 1999 8:37 PM Subject: Replication and HDR > Message from the Deja.com forum: > comp.databases.informix > Your subscription is set to individual email delivery > > > We are looking at implementing replication between 2 of our servers, a > primary in Ft. Lauderdale and the secondary in L.A., possibly using > Informix's High Availability Data Replication (HDR) tool. > > Our questions are these: > 1. The Informix manuals state that the hardware and OS must be identical > for the primary and secondary server. How much flexibility is there > on this? The Ft. Lauderdale machine is an IBM RS/6000 J30 and the L.A. > machine is an IBM RS/6000 F30. Our Ft. Lauderdale machine > has 4 CPU's and the L.A. machine has 1. We have AIX 4.3.2 running on our > primary machine in Ft. Lauderdale and AIX 4.3.1 running on > the secondary machine in L.A. Our Ft. Lauderdale machine has 512MB of > memory and the L.A. machine has 256MB. It's been recommended that we > sync the AIX versions, but I haven't gotten a definitive answer on the > hardware. Do any of these situations require changes? It's not a great > undertaking to upgrade the L.A. machine to 4.3.2. > > 2. We've found some comments on the web regarding the Informix version > to use for replication. Most of those of a positive nature recommend > using v7.31uc4, or at least v7.31uc3. We're leaning toward syncing them > at v7.31uc4, charmed with the notion that the latest should be the > greatest. > > 3. Can HDR be implemented using buffered logging instead of unbuffered > logging? The production databases on both these machines currently use > buffered logging? Are there disadvantages to doing that? > > 4. If we're configuring for a primary/secondary scenario with the > secondary to serve as a hot backup, what would be the preferred method > of transfer? Asynchronous or synchronous? > > 5. Also, the dbspaces, logical logs, physical log, and config files are > virtually the same, needing only some minor tweeking to sync them up. > > Does HDR sound like a decent solution for our requirements? We need a > hot backup server that can stand in and handle production processes in > the case of failure of the primary server in Ft. Lauderdale, with the > least amount of impact to the primary production system. No writes are > to take place on the secondary, unless the primary were to fail. The > machines can already talk to each other through the network. > > Thanks Much, > Greg > > > Sent via Deja.com http://www.deja.com/ > Before you buy. > > > > _____________________________________________________________ > Deja.com: Before you buy. > http://www.deja.com/ > * To modify or remove your subscription, go to > http://www.deja.com/edit_sub.xp?group=comp.databases.informix > * Read this thread at > http://www.deja.com/thread/%3C821u53%24dir%241%40nnrp1.deja.com%3E > > Sent via Deja.com http://www.deja.com/ Before you buy.
On Tue, 30 Nov 1999, Greg wrote: <gresmi@yahoo.com> wrote in message news:821u53$dir$1@nnrp1.deja.com... > We are looking at implementing replication between 2 of our servers, a > primary in Ft. Lauderdale and the secondary in L.A., possibly using > Informix's High Availability Data Replication (HDR) tool. > > Our questions are these: > 1. The Informix manuals state that the hardware and OS must be identical > for the primary and secondary server. How much flexibility is there > on this? The Ft. Lauderdale machine is an IBM RS/6000 J30 and the L.A. > machine is an IBM RS/6000 F30. Our Ft. Lauderdale machine > has 4 CPU's and the L.A. machine has 1. We have AIX 4.3.2 running on our > primary machine in Ft. Lauderdale and AIX 4.3.1 running on > the secondary machine in L.A. Our Ft. Lauderdale machine has 512MB of > memory and the L.A. machine has 256MB. It's been recommended that we > sync the AIX versions, but I haven't gotten a definitive answer on the > hardware. Do any of these situations require changes? It's not a great > undertaking to upgrade the L.A. machine to 4.3.2. > > 2. We've found some comments on the web regarding the Informix version > to use for replication. Most of those of a positive nature recommend > using v7.31uc4, or at least v7.31uc3. We're leaning toward syncing them > at v7.31uc4, charmed with the notion that the latest should be the > greatest. > > 3. Can HDR be implemented using buffered logging instead of unbuffered > logging? The production databases on both these machines currently use > buffered logging? Are there disadvantages to doing that? > > 4. If we're configuring for a primary/secondary scenario with the > secondary to serve as a hot backup, what would be the preferred method > of transfer? Asynchronous or synchronous? > > 5. Also, the dbspaces, logical logs, physical log, and config files are > virtually the same, needing only some minor tweeking to sync them up. > > Does HDR sound like a decent solution for our requirements? We need a > hot backup server that can stand in and handle production processes in > the case of failure of the primary server in Ft. Lauderdale, with the > least amount of impact to the primary production system. No writes are > to take place on the secondary, unless the primary were to fail. The > machines can already talk to each other through the network. > > Thanks Much, > Greg > > > Sent via Deja.com http://www.deja.com/ > Before you buy. We are currently running HADR with IDS 7.23 on HP-UX with no problems. 1) According to everything I have read, the primary and secondary servers have to be identical in almost every way - physical hardware, operating system and IDS version. If the sole purpose of the secondary server is a back-up, you could get by with one CPU. If you have to fail-over to the secondary. There could be a significant degradation in performance going from a 4 CPU machine to a 1 CPU machine. 2) Your best bet is to go with the 7.31 uc4. 3) HADR can be implemented using buffered logging. This could actually could actually contribute to a decrease in processing overhead on the primary server. 4) We are using synchronous transfer mode because it is the most secure. We are also using unbufferd logging. 5) The dbspaces, logical and physical logs should be the same. You should use a copy of the config file from the primary, then make necessary changes. The network must be stable and robust. The network must be able to handle the communication between the two servers as quickly and reliably as possible. Carlton Doe's "INFORMIX-Online Dynamic Server Handbook" is an excellent resource for configuring HADR.
Matthew, Thanks for your response. Exactly the sort of personal experience info I was looking for. Also, thanks to all others who've generously contributed, both on this forum and in personal conversation. Truly appreciated. Greg In article <006a01bf41b4$b96b5100$391e140a@in.parknet.com>, "Matthew H. Devlin III" <mdevlin@reserveamerica.com> wrote: > I have used HDR cross-country over a dedicated wan line with some success. > the systems were both e3000 Sun Machines running the same patch level of the > OS, and the same version of Informix 7.24.UC6. The system configurations > differed as far as the number of cpu's and amount of ram but that was not a > problem. We used asynchronous for performance reasons but still suffered at > times when the wan line load was high. I suspect a bigger pipe would have > alleviated most of those problems. > > ----- Original Message ----- > From: <gresmi@yahoo.com> > To: <comp.databases.informix@list.deja.com> > Sent: Tuesday, November 30, 1999 8:37 PM > Subject: Replication and HDR > > > Message from the Deja.com forum: > > comp.databases.informix > > Your subscription is set to individual email delivery > > > > > We are looking at implementing replication between 2 of our servers, a > > primary in Ft. Lauderdale and the secondary in L.A., possibly using > > Informix's High Availability Data Replication (HDR) tool. > > > > Our questions are these: > > 1. The Informix manuals state that the hardware and OS must be identical > > for the primary and secondary server. How much flexibility is there > > on this? The Ft. Lauderdale machine is an IBM RS/6000 J30 and the L.A. > > machine is an IBM RS/6000 F30. Our Ft. Lauderdale machine > > has 4 CPU's and the L.A. machine has 1. We have AIX 4.3.2 running on our > > primary machine in Ft. Lauderdale and AIX 4.3.1 running on > > the secondary machine in L.A. Our Ft. Lauderdale machine has 512MB of > > memory and the L.A. machine has 256MB. It's been recommended that we > > sync the AIX versions, but I haven't gotten a definitive answer on the > > hardware. Do any of these situations require changes? It's not a great > > undertaking to upgrade the L.A. machine to 4.3.2. > > > > 2. We've found some comments on the web regarding the Informix version > > to use for replication. Most of those of a positive nature recommend > > using v7.31uc4, or at least v7.31uc3. We're leaning toward syncing them > > at v7.31uc4, charmed with the notion that the latest should be the > > greatest. > > > > 3. Can HDR be implemented using buffered logging instead of unbuffered > > logging? The production databases on both these machines currently use > > buffered logging? Are there disadvantages to doing that? > > > > 4. If we're configuring for a primary/secondary scenario with the > > secondary to serve as a hot backup, what would be the preferred method > > of transfer? Asynchronous or synchronous? > > > > 5. Also, the dbspaces, logical logs, physical log, and config files are > > virtually the same, needing only some minor tweeking to sync them up. > > > > Does HDR sound like a decent solution for our requirements? We need a > > hot backup server that can stand in and handle production processes in > > the case of failure of the primary server in Ft. Lauderdale, with the > > least amount of impact to the primary production system. No writes are > > to take place on the secondary, unless the primary were to fail. The > > machines can already talk to each other through the network. > > > > Thanks Much, > > Greg > > > > > > Sent via Deja.com http://www.deja.com/ > > Before you buy. > > > > > > > > _____________________________________________________________ > > Deja.com: Before you buy. > > http://www.deja.com/ > > * To modify or remove your subscription, go to > > http://www.deja.com/edit_sub.xp?group=comp.databases.informix > > * Read this thread at > > http://www.deja.com/thread/%3C821u53%24dir%241%40nnrp1.deja.com%3E > > > > > > Sent via Deja.com http://www.deja.com/ > Before you buy. > Sent via Deja.com http://www.deja.com/ Before you buy.