dhis2-devs team mailing list archive

[Bob Jolliffe <bobjolliffe@xxxxxxxxx>]

Hi Orvalho

On 1 May 2013 15:07, Orvalho Augusto <orvaquim@xxxxxxxxx> wrote:

> It is true that hardware prices have decreased a lot.
>
> But for me it seems too excessive these recommendations. So I am wondering
> how we arrived to these recommendations. Would be nice if we share that.
>
> And for professional solutions it is not only one big machine you buy. You
> must have two. So when one dies you have the other ready.
>
> Some other things to be tried are:
> Instead of using one big muscular server you might need to consider to use
> one machine for webapplication and other database.
>

I agree that having a separate machine for the database can be a good
thing.  As long as they are connected with a good Gbs backbone.  This also
allows you to optimize the two machines differently.  I know in Rwanda they
have got away with fairly humble hardware so far by doing this.  Though
moving to 2.11 could still prove challenging.

Bob



>
> And the webapplication server actually can be a group of machines doing
> it; And for databases you can have just one machine for writing queries
> which is master to other servers that are only queried for reading only
> (this for MySQL have been done) or other high availability solution.
>
> For the tools to study your server, let me add some more:
> - top - The basic to see the processes and CPU usage
>
> - vmstat - This is verry important to see how your server is using the
> memory. Repeat it and check our the blocks are being used.
>
> - plotting tools based on snmp may help to profile your server; To see
> correlations between traffic/connections and CPU or memory. So you can
> consider what to change.
>
> Hope it helps.
>
> Caveman
>
>
>
>
>
> On Wed, May 1, 2013 at 12:21 PM, Dayo Adeyomoye <deemoyes@xxxxxxxxx>wrote:
>
>> Yes you are right, hardware prices are coming down plus a very good
>> server can run VMWare to properly allocate resources
>>
>> BlackBerry: 3114F90C
>> Phone: 08028851441, 08035560463
>> emails: deemoyes@xxxxxxxxx, addyraph@xxxxxxxxx
>> Yahoo IM: deemoyes
>> Facebook: pharael
>> twitter:pharaell
>>   ------------------------------
>>  *From:* Lars Helge Øverland <larshelge@xxxxxxxxx>
>> *To:* DHIS 2 developers <dhis2-devs@xxxxxxxxxxxxxxxxxxx>; "
>> dhis2-users@xxxxxxxxxxxxxxxxxxx" <dhis2-users@xxxxxxxxxxxxxxxxxxx>
>> *Sent:* Wednesday, May 1, 2013 11:16 AM
>> *Subject:* [Dhis2-users] Server specifications
>>
>> Hi all,
>>
>> in version 2.11 and later DHIS performs aggregation on-the-fly as opposed
>> to pre-aggregating data into data marts.
>>
>> This raises the bar a little on your server's specifications, mostly in
>> terms of available RAM and disk read speeds.
>>
>>
>> Some rules-of-thumb server recommendations:
>>
>>
>> - RAM: At least 1 GB memory per 1 million captured data records per month
>> or per 1000 concurrent users. At least 4 GB for a small instance, 12 GB for
>> a medium instance.
>>
>> - CPU cores: 4 CPU cores for a small instance, 8 CPU cores for a medium
>> or large instance.
>>
>> - Disk: Ideally use an SSD. Otherwise use a 7200 rpm disk. Minimum read
>> speed is 150 Mb/s, 220 Mb/s is good, 350 Mb/s or better is ideal.
>>
>>
>> So we encourage you to invest in appropriate hardware to continue to
>> benefit from all the new features in DHIS. Hardware prices are coming down
>> and value for money is increasing at vps' like linode<http://linode.com/>
>>  and digitalocean <http://digitalocean.com/>.
>>
>>
>> regards,
>>
>> Lars
>>
>> -----
>>
>> PS. For server admins, here are some tips to measure hard disk/drive read
>> speeds on Linux:
>>
>> - Use the hdparm utility which will give you approximate read speed:
>>
>> sudo hdparm -Tt /dev/sda
>>
>>
>> - If you are on a virtual server image without /dev/sda you can generate
>> a random file and test write and read speed like this:
>>
>> dd if=/dev/zero of=testfile bs=4k count=2000000
>>
>> dd if=testfile of=/dev/null bs=4k count=2000000
>>
>>
>> - To do a real-life test, you can install iotop (sudo apt-get install
>> iotop) and run it with
>>
>> sudo iotop
>>
>> then start DHIS in a new terminal and load a very large pivot table, then
>> monitor read speed from iotop. You should be seeing read speeds around 12 -
>> 25 Mb/s. Be aware that database queries will be cached after some time.
>>
>>
>>
>>
>>
>>
>>
>>
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>>
>>
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>>
>
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>