Hi, Is anyone else using Mod Auth CAS with clustered servers and shared sessions? I would be grateful for advice on how to share session state between servers.
I have colleagues using Mod Auth CAS on four clusters of eight Linux servers. Each cluster is load-balanced (without sticky sessions) and uses AFS for shared storage. Until recently CAS session files were stored on an AFS partition (the CASCookiePath). However, we've recently had some mysterious problems with Apache processes and as part of the investigation Mod Auth CAS session files were moved off the shared AFS storage and are no longer clustered. As you would expect, this is causing a *lot* more traffic to the CAS server and isn't a good solution. Simply moving back to AFS may bring scalability issues - I don't think AFS is a good fit due to frequent writes, lack of locking in AFS, sync overhead, and so on. We've seen similar situations with PHP session files. Sticky sessions aren't possible on this service as we're getting thousands of connections per second. My preference is to patch Mod Auth CAS to use Memcached, Redis or something similar to share state but this might take awhile to arrange. Has anyone already worked around this problem? Pete Birkinshaw -- Peter Birkinshaw Senior Directory and Registration Administrator IT Services Division | +44 (0)161 306 3118 The University of Manchester | PGP: 0xB7B0B433 -- You are currently subscribed to [email protected] as: [email protected] To unsubscribe, change settings or access archives, see http://www.ja-sig.org/wiki/display/JSG/cas-user
