On 09/11/2013 10:55 AM, Ian_M_Porter@xxxxxxxx wrote:
*Dell - Internal Use - Confidential * Hi, What’s a good rule of thumb to work out the number of monitors per OSDs in a cluster
This question makes little sense. The number of monitors and the number of OSDs (or any other component in the cluster for that matter) are not correlated.
The number of monitors heavily depends on the availability and resiliency you want. Higher number of monitors means your monitor cluster is less prone to data loss in the event of hardware or network failure; it also has the drawback of putting extra pressure on the monitors to get updates out -- more monitors means more acks are needed until a given update (on monitor-managed data) is considered committed.
Sure, having more monitors should help balancing the client load, but that will only happen for reads (on which clients, including OSDs, depend to get their maps updated). But then we go back to the drawbacks previously mentioned.
As a rule of thumbs, stick with 3 or 5 monitors. You'll want odd-numbers. You shouldn't need more than that, and I don't recall any deployment to date that required more than that.
If you have a big deployment, specially with a big number of OSDs and clients, feel free to experiment with multiple number of monitors and report back your findings. I'm sure I speak for pretty much everybody when I tell you those would be much appreciated :-)
-Joao
Regards Ian Dell Corporation Limited is registered in England and Wales. Company Registration Number: 2081369 Registered address: Dell House, The Boulevard, Cain Road, Bracknell, Berkshire, RG12 1LF, UK. Company details for other Dell UK entities can be found on www.dell.co.uk. _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
-- Joao Eduardo Luis Software Engineer | http://inktank.com | http://ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
