Concurrent hits limitation

[Bunny Singh]

Hi, 
 
We are going to update the RAM to 6 gb and no battery backed cache is configured.
 
> I find it hard to believe that you'll see 5000 DORAs per second, unless
>all of your clients come online at the same time. Do they?

Right now we have 48000 active clients, and i am wonder what would happen after the downtime, when lots of hits will come at the same time. Right now approx 250 concurrent connection (showing in the LB connection established option) are there for the bootps. 
 
So i just want to know what would be the sizing and the recommendation as per the Ip database and server specification.
 
Regards
Daljit Singh

--- On Mon, 1/18/10, Bunny Singh <jump2fly82 at yahoo.com> wrote:


From: Bunny Singh <jump2fly82 at yahoo.com>
Subject: Re: Concurrent hits limitation
To: dhcp-users at lists.isc.org
Cc: sthaug at nethelp.no
Date: Monday, January 18, 2010, 1:19 PM







 
 
We are using dynamic DNS update and running two scsi disk on RAID-1. We are having  IBM X3650 server with 4 gb RAM.
 
How many IP addresses do you have among your 800 subnets? What's your
lease time? What's your *target* for DHCP updates (Request/Ack) per
second?
 
We have around 2, 00,000 Ip's. Our lease time is 4 days, Target hits (DORA) will be 5000 per second.
 
Actually we are in to IPTV services so clients booting their STB's several times in a day.
 
Also Please suggest is the server failover for the huge IP database is good or  we will put the servers (without running failover protocol) behind the Loadbalance in Active Standby state.
 
Regards
Daljit Singh


--- On Mon, 1/18/10, sthaug at nethelp.no <sthaug at nethelp.no> wrote:


From: sthaug at nethelp.no <sthaug at nethelp.no>
Subject: Re: Concurrent hits limitation
To: dhcp-users at lists.isc.org, jump2fly82 at yahoo.com
Date: Monday, January 18, 2010, 12:13 PM


> I want to know about the limitation in DHCP server. Actually we are running dhcp on failover mode with 800 subnet and it will be going to expand.
>  
> I need to know how many hits (concurrent connections) dhcp services can handle.

Heavily dependent on your disk subsystem. Also on whether you use dhcpd
to perform dynamic DNS updates.

Handling DHCP requests is *disk intensive*. A good RAID subsystem with
lots of battery backed cache, or a solid state disk, will do wonders.


How many IP addresses do you have among your 800 subnets? What's your
lease time? What's your *target* for DHCP updates (Request/Ack) per
second?

Steinar Haug, Nethelp consulting, sthaug at nethelp.no




      
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