Storing leases in LDAP

[Mike.]

> if you write to LDAP and assume that once written...

if you write to LDAP and assure that once written...
.............................^

Big difference, and an important one as well.



On 3/10/2015 at 12:01 PM Leigh Porter wrote:

|I guess you make sure your LDAP server is fast enough to cope. Since
the
|bottleneck with DHCP servers is typically the sync to disk, if you
write
|to LDAP and assume that once written the record is safe is could
actually
|be faster than writing to local disk.
|
|Ultimately, LDAP write speed depends on the backend you use for
LDAP.
|There are a load of LDAP tuning hints for OpenLDAP available.
|
|Given that lots of people fudge the performance by making the leases
file
|be written to memory instead of real disk and then backup the file
from
|memory to disk, the point of forcing a sync to ensure you write to
disk
|goes away.
|
|If you could have an in-memory database across a couple of servers
(or a
|multi-master something or other such as LDAP) then you get a good
solution
|without this (IMO) horrid leases file stuff.
|
|See here for some OpenLDAP write perf data:
|
|http://ldapcon.org/2011/downloads/hummel-slides.pdf
|
|
|--
|Leigh
|
|
|-----Original Message-----
|From: dhcp-users-bounces at lists.isc.org
|[mailto:dhcp-users-bounces at lists.isc.org] On Behalf Of Simon Hobson
|Sent: 10 March 2015 11:50
|To: Users of ISC DHCP
|Subject: Re: Storing leases in LDAP
|
|Ben Humpert <ben at an3k.de> wrote:
|
|> Is any version capable of maintaining the list of DHCP leases in
LDAP 
|> instead of the dhcpd.leases file?
|
|I suspect the answer is going to be no, and no it's not likely to
happen.
|Storing the config in LDAP is one thing - it's not really that
performance
|sensitive. But storing leases is typically one of the performance
|bottlenecks on a DHCP server. Whenever a lease is given to a client,
the
|server stores that lease in the leases file *and syncs it to disk* -
I
|believe this is done before the packet is sent to the client but I
could
|be wrong on that.
|What happens to performance if you have to update an LDAP database
rather
|than just appending a record to a text file ?
|
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