From: Ryan_Hoffman on
I'm doing some research on network performance requirements for
database applications. I was wondering if anyone in this group would
be willing to share their opinions regarding specific values that
should be used as targets (latency/delay, jitter, packet loss).
Various vendor documentation provides some guidelines (latency: Oracle
SYNC = ≤ 10 ms, SQL Clustering ≤ 100 ms; loss: Oracle On Demand ≤
0.1%). I was hoping to hear what database administrators look for
when purchasing wide area network services.

Thanks!
From: Frank van Bortel on
Ryan_Hoffman wrote:
> I'm doing some research on network performance requirements for
> database applications. I was wondering if anyone in this group would
> be willing to share their opinions regarding specific values that
> should be used as targets (latency/delay, jitter, packet loss).
> Various vendor documentation provides some guidelines (latency: Oracle
> SYNC = ≤ 10 ms, SQL Clustering ≤ 100 ms; loss: Oracle On Demand ≤
> 0.1%). I was hoping to hear what database administrators look for
> when purchasing wide area network services.
>
> Thanks!

Never heard any DBA being consulted before LAN and/or WAN
purchases.
DBA's usually learn to live with the "It's the database that's
performing badly!" accusations afterwards. By then, the seagull
known as interim manager or sales consultant is flown.

--

Regards, Frank van Bortel

Topposting in Usenet groups I regard as offensive - I will not reply
From: vsevolod afanassiev on
Requirements vary from application to application. Well-written
application cache static data.
There are several network-related statistics, this is from Statspack
report for 9.2.0.8 database:

Statistic Total per Second
per Trans
--------------------------------- ------------------ --------------
------------
SQL*Net roundtrips to/from client 15,714,040
436.5 22.2
bytes received via SQL*Net from c 5,056,985,913
140,475.7 7,144.4
bytes sent via SQL*Net to client 3,173,523,378
88,155.9 4,483.5



From: joel garry on
On Feb 3, 2:28 pm, vsevolod afanassiev <vsevolod.afanass...(a)gmail.com>
wrote:
> Requirements vary from application to application. Well-written
> application cache static data.
> There are several network-related statistics, this is from Statspack
> report for 9.2.0.8 database:
>
> Statistic                                      Total     per Second
> per Trans
> --------------------------------- ------------------ --------------
> ------------
> SQL*Net roundtrips to/from client         15,714,040
> 436.5         22.2
> bytes received via SQL*Net from c      5,056,985,913
> 140,475.7      7,144.4
> bytes sent via SQL*Net to client       3,173,523,378
> 88,155.9      4,483.5

A single application is the wrong level to determine this. The dba
presumably is responsible for allocuting all Oracle related network
usage. So, at a minimum, it would need to be statistics as above for
all applications current and contemplated, projected forward, plus the
likelihood of disaster or distributed usage. The latter means
archiving transport, and rman usage over the net (among other
possibilities). For example, to build a standby database you have to
figure how much data there is uncompressed (in case there happens to
be some bug that disallows the compression option), and how fast you
will need to rebuild such a beast from scratch should the archive gap
become untenable. If management's view is "no, we will never lose our
computer room due to the upstairs crapper overflowing," get an
experienced consultant in there.

Another way to get around penny-pinching network resources is to get a
video conferencing project, that means big pipes for everyone.

jg
--
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That darn internet! http://www.signonsandiego.com/news/2010/feb/04/man-pleads-guilty-in-la-to-posting-film-online/
From: Tim X on
joel garry <joel-garry(a)home.com> writes:

> On Feb 3, 2:28 pm, vsevolod afanassiev <vsevolod.afanass...(a)gmail.com>
> wrote:
>> Requirements vary from application to application. Well-written
>> application cache static data.
>> There are several network-related statistics, this is from Statspack
>> report for 9.2.0.8 database:
>>
>> Statistic                                      Total     per Second
>> per Trans
>> --------------------------------- ------------------ --------------
>> ------------
>> SQL*Net roundtrips to/from client         15,714,040
>> 436.5         22.2
>> bytes received via SQL*Net from c      5,056,985,913
>> 140,475.7      7,144.4
>> bytes sent via SQL*Net to client       3,173,523,378
>> 88,155.9      4,483.5
>
> A single application is the wrong level to determine this. The dba
> presumably is responsible for allocuting all Oracle related network
> usage. So, at a minimum, it would need to be statistics as above for
> all applications current and contemplated, projected forward, plus the
> likelihood of disaster or distributed usage. The latter means
> archiving transport, and rman usage over the net (among other
> possibilities). For example, to build a standby database you have to
> figure how much data there is uncompressed (in case there happens to
> be some bug that disallows the compression option), and how fast you
> will need to rebuild such a beast from scratch should the archive gap
> become untenable. If management's view is "no, we will never lose our
> computer room due to the upstairs crapper overflowing," get an
> experienced consultant in there.
>
This is very critical. Estimating growth is almost always udner
estimated. come up with a figure and then multiply by PI and you may be
getting closer to what reality is. I've frequently seen analysis that
has focused on the app performance and completely overlooked network
requirements for backups. If you expect to have, lets say, one full
backup per week and incremental backups each day, then you need to be
able to perform them within at least one 24 hour period - this means all
your databases AND other critical data, such as file servers, mail
servers etc. While many SANs and other products, including Oracle,
provide means to assist in getting a consistent snapshot of data for
backup, you usually need to transfer that data to a backup machine where
it is put onto tape etc. Often, that backup is either off site or the
tapes are stored off site for DR reasons. The critical point is that you
need to be able to do this all within a single backup period (often this
is 1 day, but for some sites/appps, it cold be more frequent). If you
cannot transfer all your data in a backup period, then things get really
complicated fast. The point to note is that this backup process usually
involves mroe than just your Oracle data AND it normally takes place at
the same time your other activities are occuring i.e. it is a mistake to
estimate network loads based solely on the requirements of the 'public'
applications. You need to add in the overheads from admin/maintenance
activities, such as backups.

then, be careful regarding how network vendors spin their
specifications. I came across one of the larger vendors who claimed a
switch they sell was capable of 10 Gbit sec speeds. However, on further
investigating it, it turned out this speed could only be achieved by
multiplexing 10 1Gbit connections and that the switch limited individual
connections to 1Gbit. So, if you needed 10Gbit between two machines that
passed through this switch, you had to have multiple NICs in each
machine! Even the reseller was not aware of this limitation and thought
the switch could do up to 10Gbit on a single connection.

I personally would strongly suggest getting in a network specialist. The
network vendors have really been into a lot of value adding in the last
few years. Switches are no longer just switches. They come with all
sorts of features, such as built-in anti-virus protection, switch level
authentication, deep and shallow packet inspection, etc. Its very easy
to shoot yourself in the foot, especially if you have a heterogeneious
network with equipment from different vendors.

> Another way to get around penny-pinching network resources is to get a
> video conferencing project, that means big pipes for everyone.

hehehe! Tell them they need not just video conferencing, but the full
video grid stuff (aka VC inspired by Star Trek's holodeck).

--
tcross (at) rapttech dot com dot au