Any opinions about RAID vs JBOD?
Options I can think of:
1) LVM. 8 disks, RAIDed, for data. 1 disk for mysql_temp,
1 disk for system and Qserv software etc
2) JBOD. Problem: we need to deal with distributing data
across disks. AndyS: how difficult would it be to extend
the loader so that it shards chunks (say round robin)
across multiple disks on a machine (and do symlink for
each table in mysql_data directory)? Unless Andy can
easily do it in loader, I think I'd rather not go there
now, because it will add another level of complexity and
delay testing.
3) JBOD. We use mysql partitioning to distribute data
across 8 disks. Probably easier than "2", but still,
it is an extra level of complexity, will delays tests.
I am tempted to just go with "1" unless Andy can magically
enhance the loader easily.
Opinions?
Jacek
I am leaning towards JBOD, 8 disks for data
On 01/16/2015 04:34 AM, Yvan Calas wrote:
> Hi,
>
>> On 15 Jan 2015, at 00:16, Fabrice Jammes <[log in to unmask]> wrote:
>>
>> Here's what Qserv team would like to have on the cluster, in addition to what we have defined previously:
>>
>> - Scientific Linux on all node, in order to get C++11 support
>
> Do you need SL7 only because of C++11, or is there any other reason? Is it possible to have full C++11 support on SL6 nodes actually?
>
> As I already told you, it might take time to install SL7 on servers at CC-IN2P3 (probably 2 months or more).
>
>> - 10TB shared storage available for all nodes and able to support a large amount of io during data-loading
>
> The features of the new Dell machines are as follow:
>
> - DELL PowerEdge R620
> + 2 x Processors Intel Xeon E5-2603v2 1.80 Ghz 4 cores, 10 Mo cache, 6.4 GT/s , 80W
> + RAM: 16 Go DDR-3 1600MHz (2x8Go)
> + 10 x 1 TB disk Nearline SAS 6 Gbps 7200 Tpm 2,5" - hotplug
> + 1 x RAID card H710p with 1 GB nvram
> + 1 x 1 GbE with 4 ports Broadcom® 5720 Base-T card
> + 1 x iDRAC 7 Enterprise card
> + redundant power supply
>
>> and some questions:
>>
>> - what will be the disk architecture (which kind of RAID, or something else, or nothing?)
>
> Since there is 10TB on each server, we plan to configure them in RAID-6 (2 parity disks - 7.4 TB available), or in RAID-5 (one parity disk - 8.4TB available) in you need more space on each node. If you are thinking of another better RAID configuration for qserv, please let us know ;)
>
> Note that we plan to install the 25 first machines int the computing center at the beginning of week 5 (26-27/01/2015).
>
>> - we don't know a lot about Puppet and would like to know which kind of feature it offers (system monitoring, service restart, ...)?
>
> qserv admins at CC-IN2P3 (mainly myself) will write a puppet module in order to:
>
> - deploy the qserv software automatically,
> - tune the OS and qserv parameters.
>
> Moreover, since the soft will run as qserv user (as it was the case last year on the 300+ nodes), I guess that you will be able to restart the service, change qserv configuration files if needed, etc. using sudo.
>
> The monitoring will be based on Nagios (probes to define and write) and collectd/smurf mainly. However plots generated by smurf will be only accessible from inside CC-IN2P3. If some extra monitoring is needed, we will deploy it.
>
>
>> Would it be possible to talk to a Puppet/monitoring expert when these kind of questions occurs?
>
> I am not an expert of puppet, but I can try to answer to all of your questions ;) If I don't know the answer, I will ask to Mattieu, and if really needed you can contact him directly.
>
> Cheers,
>
> Yvan
>
>
> ---
> Yvan Calas
> CC-IN2P3 -- Storage Group
> 21 Avenue Pierre de Coubertin
> CS70202
> F-69627 Villeurbanne Cedex
> Tel: +33 4 72 69 41 73
>
>
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