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Re: Regd MySQL Cluster Startup phases
Posted by: Mikael Ronström
Date: July 01, 2005 03:40PM

Hi,
Regarding removing the local checkpoint at start it is not absolutely necessary, it is more to
avoid that multiple errors will give you a system that can no longer be restarted at all and
you need to start from a backup.

So it can be removed (with a small programming effort) but will then slightly increase the
risk associated with restarts. So as usual there is a trade-off.

We'll keep it in mind that this is desirable and a possible solution could be to introduce a
config variable that specifies which way to go about it.

Thx for your input and sharing with us where you see improvements possible.

It should also be possible to decrease start-time by using more disks in a RAID manner thus
increasing the disk read/write speed since that is really the bottleneck for the system restart
(except the index rebuild which is a CPU activity).

Rgrds Mikael

Balasubramanian Azhagappan wrote:
> We are currently checking, how much time it takes
> for the Mysql Cluster to startup.
>
> right now we have 5 Million entries in 6 tables,
> with each each row(from each table)added up gives
> around 1084KB.
> total size comes around 10GB of data in Memory
> when loaded.
>
> We have a configured 7 machines in the cluster
> each machine, of which 2 machines with 12GB RAM is
> configured for the ndbd daemons and the rest 5
> machines is alloted for the daemon.
>
> node3, node5 are in 1 of the ndbd machine and
> node2 and node4 are in another ndbd machine.
>
>
> We have set the
> NoOfDiskPagesToDiskDuringRestartTUP=500 (around
> 40MB)
> NoOfDiskPagesToDiskDuringRestartACC=500 (around
> 40MB)
>
> and we have a 15K-RPM SCSI harddisk in the ndbd
> machines.
>
> During our observation, we found that the
> following major time consuming phases
>
> 1. IndexActivation takes around 3-4Mins
> 2. LocalCheckPoint after Step3(System Restart)
> takes 13-14Mins
> 3. Index Rebuild done - takes 3.4Mins
>
> Totalling to around 23-24Mins.
>
> I would like to know whether it is possible to
> bring the start up time within 10 mins including
> all the above 3 major phases.
>
> If not, is it possible to skip the LocalCheckPoint
> during restart.
>
> Thanks in advance.
>
> regards,
> Bala

Mikael Ronstrom
Senior Software Architect, MySQL AB
My blog: http://mikaelronstrom.blogspot.com

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Re: Regd MySQL Cluster Startup phases
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July 01, 2005 03:40PM


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