Message from discussion Log Shipping - database expansion
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From: Antony <albion26....@gmail.com>
Subject: Re: Log Shipping - database expansion
Date: Thu, 23 Feb 2012 20:03:54 -0800 (PST)
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On Friday, 17 February 2012 09:37:34 UTC+13, Richard wrote:
> On Feb 14, 11:00=A0pm, RJha <resheersh....@gmail.com> wrote:
> Thanks for the reply.
> We looked at Rep-Server. In fact, we trialed the product. We had
> three issues:
> - cost (priced based on cores on box, not CPU's allocated to lpar. An=
lpar running with one CPU on hardware with eight cores would be
> priced based on the 8 cores, not the one CPU).
As of RS 15.5 Sybase now support sub-capacity licensing - so a 1 core VM on=
an 8 core host will only cost 1 core license. Logical partitions are also=
supported I think (e.g. Solaris containers).
> - it's a complex product. High level of understanding required,
> particularly if something goes wrong. Seemed like overkill for the chall=
enge we were trying to address.
Warm standby setup is very simple. It's as complex as you want to make it r=
eally - though you do need to get used to the product, it's nothing like AS=
> - we break the transaction chain in a number of databases during
> our nightly processing. Re-establishing syncronization after that was no=
> simple process, that we felt would require non-trivial shell scripting wo=
Do you know why this happens? Not everything is 100% compatible with replic=
ation (whether viw RepServer or other), but most things should work. If it'=
s just Warm Standby you're using, you can sync with dump/load right? Not th=
at hard, but it is time consuming if the db is large.
> > 2. You can also do the data copy at SAN level using SAN technology
> > like SRDF in EMC world.
> Our sites are 400 miles apart. We were told network latency would
> impact app performance.
Indeed. You would need to use SRDF/S (synchronous) which hammers your IO th=
roughput. Sybase do not support SRDF/A (asynchronous) as the database may b=
e corrupted if the disk pairs are not in sync when split.