On 09/02/2011 09:34, "guest01" <guest01@xxxxxxxxx> wrote: >Hi, > >We are currently using Squid 3.1.10 on RHEL5.5 and Kerberos >authentication for most of our clients (authorization with an icap >server). At the moment, we are serving approx 8000 users with two >servers. Unfortunately, we have performance troubles with our Kerberos >authentication. Load values are way tooooo high ... > >10:19:58 up 16:14, 2 users, load average: 23.03, 32.37, 25.01 >10:19:59 up 15:37, 2 users, load average: 58.97, 57.92, 47.73 > >Peak values have been >70 for the 5min interval. At the moment, there >are approx 400 hits/second (200 per server). We already disabled >caching on harddisk. Avg service time for Kerberos is up to 2500ms >(which is quite long). > >Our kerberos configuration looks pretty simple: >#KERBEROS >auth_param negotiate program >/opt/squid/libexec/negotiate_kerberos_auth -s HTTP/fqdn -r >auth_param negotiate children 30 >auth_param negotiate keep_alive on > >Is there anyway for further caching or something like that? > >For testing purposes, we authenticated a certain subnet by IP and load >values decreased to <1. (Unfortunately, this is not possible because >every user gets a policy assigned by its username) > >Any ideas anyone? Are there any kerberos related benchmarks available >(could not find any), maybe this issue is not a problem, just a >limitation and we have to add more servers? > >Thanks! > >best regards >Peter Peter, I have pretty much the same setup as you - just 3.1.8, though only 700 users. Have you disabled the replay cache: http://wiki.squid-cache.org/ConfigExamples/Authenticate/Kerberos But beware of a memory leak (depending on your libs of course): http://squid-web-proxy-cache.1019090.n4.nabble.com/Intermittent-SquidKerbAu th-Cannot-allocate-memory-td3179036.html. I have a call outstanding with RH at the moment. Are your rules repeating requesting authentication unnecessarily when it's already been done? Amos was very helpful when advising on this (search for the post..) 8000 users.. Only 30 helpers? What does cachemgr say about used negotiate helper stats, timings/sec etc. Is your krb5.conf using the nearest kdc in it's own site etc? Some load testers out there incorporate Kerberos load testing. Just my thoughts.. Nick > The information contained in this e-mail is of a confidential nature and is intended only for the addressee. If you are not the intended addressee, any disclosure, copying or distribution by you is prohibited and may be unlawful. Disclosure to any party other than the addressee, whether inadvertent or otherwise, is not intended to waive privilege or confidentiality. Internet communications are not secure and therefore Conde Nast does not accept legal responsibility for the contents of this message. Any views or opinions expressed are those of the author. The Conde Nast Publications Ltd (No. 226900), Vogue House, Hanover Square, London W1S 1JU
