We have a 100 Mb dedicated DR link to another data center.  Want to set up a 
SQL 2008 database to use mirroring from primary to a standby server at the 
remote data center.  I did a ping test and here is the result.

ping -n 100 -l 5120 <target IP>

Ping statistics for <target IP>
    Packets: Sent = 100, Received = 99, Lost = 1 (1% loss),
Approximate round trip times in milli-seconds:
    Minimum = 8ms, Maximum = 19ms, Average = 11ms

is the network latency good enough for database mirroring?  Does anyone know 
the min. requirement?  Field experience will be fine too.

Thanks.

depends a lot on how busy the DB is and what sort of mirroring you do.

basically two types (3, but one is a variation of the other)

high protection or performance. the difference is that the high protection 
doesnt commit the transaction on the primary server until the secondary 
server acknowldges it has it. this has a direct impact on the speed of the 
primary server. with performance the primary just sends the data off to the 
secondary and it assumes it gets it ok and it keeps doing its thing. this 
wont impact the primary use but can lead to corruption or other data 
integratity issues if the primary goes down.

i setup high protection between two data centers that had a 10GB pipe 
between them (ping returns 1ms or less) and it wasnt even close to 
acceptable. in basically decreased the performance by 16 fold, and i was the 
only user on the system.

an important questions to ask when setting up DR is how close do they need 
to be? ie, how much data loss can you have? one day? one hour? one min?

you might want to look at log shipping or something else. my guess is that 
it just wouldnt work.

Justin



"Chris" <Chris@discussions.microsoft.com> wrote in message 
news:0A71E4CF-1D4F-448B-BC17-656845C86802@microsoft.com...
> We have a 100 Mb dedicated DR link to another data center.  Want to set up 
> a
> SQL 2008 database to use mirroring from primary to a standby server at the
> remote data center.  I did a ping test and here is the result.
>
> ping -n 100 -l 5120 <target IP>
>
> Ping statistics for <target IP>
>    Packets: Sent = 100, Received = 99, Lost = 1 (1% loss),
> Approximate round trip times in milli-seconds:
>    Minimum = 8ms, Maximum = 19ms, Average = 11ms
>
> is the network latency good enough for database mirroring?  Does anyone 
> know
> the min. requirement?  Field experience will be fine too.
>
> Thanks.