Type of Replication to be used.
A user running Informix 7.31 asked whether to use HDR or Enterprise Replication (ER) for a disaster-recovery site. The consensus from several respondents: HDR is far simpler to set up and maintain and mirrors the whole instance, but requires near-identical hardware, chunk sizes/layouts and is sensitive to network latency; the secondary is read-only until failover. ER is more complex but flexible — different hardware, selected tables/columns, and updates on both servers. Advice was to use HDR unless multi-site updates or partial replication are needed; also consider whether the DR box will be used for reporting/testing. Neither works well through NAT'd firewalls. The poster thanked the group; no specific implementation outcome is recorded.
Auto-generated by DrWatson from the posts below — may be imperfect; read the full thread.
Hi Informix gurus, We are planning to setup a DR site. In our production enviornment we have Informix database 7.31. We are planning to use replication feature of Informix for setting up the DR. Please suggest me with the type of replication(HDR and ER) to be used between DR and production site. Regards, Shailesh M
Shailesh It depends in the first instance on your hardware. If primary and secondary are different you have no choice but to use ER, even if you want to replicate the entire instance. If primary and secondary have identical/very similar hardware, and you can achieve identical chunks sizes and layouts, you can use either and the decision depends on what you want to achieve. If you simply want the secondary to be a hot standby for the primary (full database size and layout, transaction replicated immediately, no user access until primary crashes (enquiry only is permitted)) then you can use HDR. If, however, you want to only copy certain tables, or allow users to update on both servers then you will need to use ER. Keith -----Original Message----- From: Shailesh.Mo.... [mailto:Shailesh.More@ril.com] Sent: Friday, April 16, 2004 10:16 To: ids@iiug.org Subject: Type of Replication to be used. [2827] Hi Informix gurus, We are planning to setup a DR site. In our production enviornment we have Informix database 7.31. We are planning to use replication feature of Informix for setting up the DR. Please suggest me with the type of replication(HDR and ER) to be used between DR and production site. Regards, Shailesh M ******************************************************************************** ** This message is sent in strict confidence for the addressee only. It may contain legally privileged information. The contents are not to be disclosed to anyone other than the addressee. Unauthorised recipients are requested to preserve this confidentiality and to advise the sender immediately of any error in transmission. This footnote also confirms that this email message has been swept for the presence of computer viruses, however we cannot guarantee that this message is free from such problems. ******************************************************************************** **
thanks for ur suggesstion. Regards, Shailesh M "Simmons, Keith" <keith.simmons@office2 To: "'Shailesh.Mo....'" <Shailesh.More@ril.com>, ids@iiug.org office.biz> cc: Subject: RE: Type of Replication to be used. [2827] 04/16/2004 04:19 PM Importance: Normal Sender's OU: Reliance |------------------| | [ ] Confidential | |------------------| Shailesh It depends in the first instance on your hardware. If primary and secondary are different you have no choice but to use ER, even if you want to replicate the entire instance. If primary and secondary have identical/very similar hardware, and you can achieve identical chunks sizes and layouts, you can use either and the decision depends on what you want to achieve. If you simply want the secondary to be a hot standby for the primary (full database size and layout, transaction replicated immediately, no user access until primary crashes (enquiry only is permitted)) then you can use HDR. If, however, you want to only copy certain tables, or allow users to update on both servers then you will need to use ER. Keith -----Original Message----- From: Shailesh.Mo.... [mailto:Shailesh.More@ril.com] Sent: Friday, April 16, 2004 10:16 To: ids@iiug.org Subject: Type of Replication to be used. [2827] Hi Informix gurus, We are planning to setup a DR site. In our production enviornment we have Informix database 7.31. We are planning to use replication feature of Informix for setting up the DR. Please suggest me with the type of replication(HDR and ER) to be used between DR and production site. Regards, Shailesh M ******************************************************************************** ** This message is sent in strict confidence for the addressee only. It may contain legally privileged information. The contents are not to be disclosed to anyone other than the addressee. Unauthorised recipients are requested to preserve this confidentiality and to advise the sender immediately of any error in transmission. This footnote also confirms that this email message has been swept for the presence of computer viruses, however we cannot guarantee that this message is free from such problems. ******************************************************************************** **
> -----Original Message----- > From: forum.subscriber@iiug.org [mailto:forum.subscriber@iiug.org]On Shailesh.Mo.... wrote > > We are planning to setup a DR site. > > In our production enviornment we have Informix database 7.31. We are > planning to use replication feature of Informix for setting up the DR. > > Please suggest me with the type of replication(HDR and ER) to be used > between DR and production site. HDR is simple to use, easy to maintain HDR needs similar hardware for secondary server. ER is more complicated to set up, harder to maintain. ER is more flexible. Different hardware, different databases, different fields in tables. ER will allow updating of records on secondary server. If you can manage with HDR, that would be my first choice. Colin Bull c.bull@videonetworks.com
Shailesh, What you implement may depend on your planned use of the DR site. Is it truly just DR, or will it also be used for testing other things (such as DB reorgs as we do). Might it be used for load balancing for current servers or will it truly be dormant unless a disaster occurs. Might it be used additionally as a report runner for period/quarter end processing or such.. I think if you send a bit more input to these gurus, they can give you a more comprehensive answer. We have a DR, but we don't use Informix HDR or ER, we have a hardware/disk copy solution. Our DR has also been used to test DB reorgs (only system we have that is exactly like production), and it has also been used on occasion to break from production before a project major go-live weekend to have something to reference in the event the production go-live has glitches. have fun planning, sounds like a good time :) Norma Jean -----Original Message----- From: Shailesh.More@ril.com [mailto:Shailesh.More@ril.com] Sent: Friday, April 16, 2004 4:16 AM To: ids@iiug.org; forum.subscriber@iiug.org Subject: Type of Replication to be used. [2827] Hi Informix gurus, We are planning to setup a DR site. In our production enviornment we have Informix database 7.31. We are planning to use replication feature of Informix for setting up the DR. Please suggest me with the type of replication(HDR and ER) to be used between DR and production site. Regards, Shailesh M ----------------------------------------- ============================================================ The information contained in this message may be privileged and confidential and protected from disclosure. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any reproduction, dissemination or distribution of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by replying to the message and deleting it from your computer. Thank you. Tellabs ============================================================
HDR is the simplest and easiest replication to set up for DR. It maintains an exact replica of the production server. The DR server must be just like production server. ER is typically used for replicating subsets of production data so setting it up for replication of the entire production database is more complex and time consuming. Christine Normile I/T Specialist, Informix Solutions Data Management Worldwide Technical Enablement Telephone: 877-252-5399 T/L 273-0981 Mobile: 210-365-5073 "Shailesh.Mo...." <Shailesh.More@ril.com> Sent by: forum.subscriber@iiug.org 04/16/2004 04:15 AM To: ids@iiug.org cc: Subject: Type of Replication to be used. [2827] Hi Informix gurus, We are planning to setup a DR site. In our production enviornment we have Informix database 7.31. We are planning to use replication feature of Informix for setting up the DR. Please suggest me with the type of replication(HDR and ER) to be used between DR and production site. Regards, Shailesh M
I'd add that network latency is important with HDR, less so with ER. Neither, in my experience, liking going through Nat'd firewalls Colin Bull wrote: > > > -----Original Message----- > > From: forum.subscriber@iiug.org [mailto:forum.subscriber@iiug.org]On > Shailesh.Mo.... wrote > > > > We are planning to setup a DR site. > > > > In our production enviornment we have Informix database 7.31. We are > > planning to use replication feature of Informix for setting up the DR. > > > > Please suggest me with the type of replication(HDR and ER) to be used > > between DR and production site. > > HDR is simple to use, easy to maintain > HDR needs similar hardware for secondary server. > > ER is more complicated to set up, harder to maintain. > ER is more flexible. Different hardware, different databases, different fields in tables. > ER will allow updating of records on secondary server. > > If you can manage with HDR, that would be my first choice. > > Colin Bull > c.bull@videonetworks.com -- Paul Watson # Oninit Ltd # Growing old is mandatory Tel: +44 1436 672201 # Growing up is optional Fax: +44 1436 678693 # Mob: +44 7818 003457 # www.oninit.com #
I agree with Christine. Unless you have a special need to update at multi= ple sites, HDR is by far the easiest to set up and maintain. As you migra= te to 9.4, it is even better. Larry Sorensen I/T Consultant ----- Original Message ----- From: Christine N.... Sent: Friday, April 16, 2004 8:14 AM To: ids@iiug.org Subject: Re: Type of Replication to be used. [2833] =20 HDR is the simplest and easiest replication to set up for DR. It =20 maintains an exact replica of the production server. The DR server must =20 be just like production server. ER is typically used for replicating =20 subsets of production data so setting it up for replication of the entir= e =20 production database is more complex and time consuming. Christine Normile I/T Specialist, Informix Solutions Data Management Worldwide Technical Enablement Telephone: 877-252-5399 T/L 273-0981 Mobile: 210-365-5073 "Shailesh.Mo...." <Shailesh.More@ril.com> Sent by: forum.subscriber@iiug.org 04/16/2004 04:15 AM To: ids@iiug.org cc: =20 Subject: Type of Replication to be used. [2827] Hi Informix gurus, We are planning to setup a DR site. In our production enviornment we have Informix database 7.31. We are planning to use replication feature of Informix for setting up the DR. Please suggest me with the type of replication(HDR and ER) to be used between DR and production site. Regards, Shailesh M