Re: mirroring - pros & cons
On May 12, 9:50 am, Art Kagel <art.ka...@gmail.com> wrote: > What is the underlying disk structure? If the chunks are mirrored (say > RAID1 or RAID10) on disk then the Informix mirrors are redundant and are > costing you throughput. If on the other hand, your disks are not mirrored > (no RAID, RAID0, or <ick> RAID5) there is some benefit to mirroring them. > > Art > > Art S. Kagel > Advanced DataTools (www.advancedatatools.com) > IIUG Board of Directors (a...@iiug.org) > > See you at the 2010 IIUG Informix Conference > April 25-28, 2010 > Overland Park (Kansas City), KSwww.iiug.org/conf > > Disclaimer: Please keep in mind that my own opinions are my own opinions and > do not reflect on my employer, Advanced DataTools, the IIUG, nor any other > organization with which I am associated either explicitly, implicitly, or by > inference. Neither do those opinions reflect those of other individuals > affiliated with any entity with which I am affiliated nor those of the > entities themselves. > > > > On Tue, May 11, 2010 at 5:03 PM, Tom Lehr <tomc...@gmail.com> wrote: > > We have mirrored db spaces on our production OLTP system - rootdbs, > > physical log dbs and logical logs dbs. I can see the value for doing > > this on rootdbs but am unsure of the other two so much. The reason our > > system is as such is more out of years of habit from past DBA's, > > sysadmins, etc. I am now reviewing whether this is the wisest course > > and why we would or would not keep things like this - especially for > > any future new hardware systems. Any feedback, input, comments or > > suggestions is appreciated > > Thanks! > > _______________________________________________ > > Informix-list mailing list > > Informix-l...@iiug.org > >http://www.iiug.org/mailman/listinfo/informix-list "We" always said "always mirror your critical dbspaces somehow...", whether it be Informix mirroring or hardware mirroring. As stated in this thread, the engines "critical dbspaces are one such as the rootdbs, any dbspace with logical or physical log files, etc YOU get to determine which other dbspaces you consider critical. I definitely prefer hardware mirroring now for multiple reasons. Recovery of a dbspace mirrored within IDS ("informix mirroring") can take quite some time depending on the size of the dbspace and the time it's primary chunk(s) have been down. Hardware level mirroring is typically much faster, although that of course depends on a number of things. I defer to Art's comments on any RAID issues as he stated so well. Thanks - Mark Scranton www.markscranton.com