Re: Q: Mirroring - what is the better way

>>>>> "Cheuk" == Cheuk Kong Lo <cklo@news.hk.super.net> writes: Cheuk> Cheuk> David Williams (djw@smooth1.demon.co.uk) wrote: Cheuk> : According to the person at Informix UK Training who gave my Cheuk> : Performance Tuning course....there is no difference. Mirroring is Cheuk> : mirroring. Cheuk> Cheuk> : YOu have to remember some OS's do not including OS mirroring. On Cheuk> : these machines Informix mirroring is the only choice. Cheuk> Cheuk> : I suspect Informix only developed their mirroring because OS's Cheuk> : at the time did not include mirroring... Cheuk> Cheuk> The other guy at Informix told me that we should always use Informix Cheuk> Mirroring that Informix has complete control over it. I'm sorta agree, Cheuk> if ever I would go mirroring, because there's only one party of blame Cheuk> if that doesn't work...:-) Cheuk> Like most things you have tradeoffs... you can let Informix handle the mirror but as been noted, the performance would be slower than at the OS level. The person doing the training obviously doesn't understand device drivers and s/w layers... oh well... Another thing to consider is that with the OS (and depending on the OS) you can plex to more than one device. The idea here would be to break the plex and do a cold backup on those devices and re-initiate the plex. -- Pablo Sanchez | Ph # (650) 933.3812 Fax # (650) 933.2821 pablo@sgi.com | Pg # (800) 930.5635 -or- pablo_p@pager.sgi.com ------------------------------------------------------------------------------- I am accountable for my actions. http://reality.sgi.com/pablo [ /Sybase_FAQ ]