I am trying to get a reliable/consistent answer as the first attachment seems
to indicate EMC endorse MS SQL mirroring (though my EMC sales person is
strongly proposing EMC SRDF over MS SQL DB mirroring, saying that SRDF
is more reliable than MS SQL mirroring & he quoted a few reference sites
using SRDF for MS SQL DR recovery with zero RPO
Attachment 2 is a product DoubleTake which mentions that synchronous
SAN replication has a distance limit of 10 miles (about 16 km)
However, link below (from EMC) mentions the WAN (fibre link, guess it refers
to dark fibre though our EMC Sales said dark fibre is not essential, copper
IP link suffice as our current link is copper) has a max of 300km.
so who is right? Is it 10 miles max distance or 300km?
My DBA colleague mentioned that SQL DB mirroring also has a max distance
limit (for WAN) but some internet links out there says there's no limit. Eg:
So who's right & what's the distance limit for MS SQL mirror if any?
I seem to read somewhere (but lost track of that url/link) that for MS SQL DB
mirroring (synchronous), certain tables (like tempfiles or tempspace ?). Can
someone list out all the tables that can't be mirrored & are these tables crucial?
Besides cost, appreciate if anyone can share any other comparisons, pros/cons
of both technologies as finding it hard to decide. If anyone has done Oracle
DB synchronous mirroring before, can share how you feel about it. Any
SRDF replication experience are most welcome as well. It costs almost
US$100k more here to have SRDF.