Forum Discussion
dogg_dogg_23774
Nimbostratus
NimbostratusLoad-balancing cache arrays in V9
Hi,
I am rather new to iRule and need some assistance to load-balance forward proxy caching arrays. I understand we have been able to create iRule like below in V4, but, since I heard we do not support cache rule at this time, I am trying to accomplish the same behavior using other techniques. Is there any sample that I can use for my reference?
rule cache_rule {
cache ( http_uri ends_with "html" or http_uri ends_with "gif" ) {
origin_pool origin_server
cache_pool cache_servers
hot_pool hot_cache_servers
}
}
Thanks in advance,
5 Replies
- There are cache commands available in iRules, actually. You can find a list of them in the iRules wiki here: Click here. The cache commands do require an add-on license, though, so they aren't available in a default v9 installation.
HTH,
Colin 
dogg_dogg_23774thanks for the response.
Actually what I was looking for was do something equivalent as below rather than using RAMCache feature introduced in V9...
http://tech.f5.com/home/bigip/manuals/bigip4_5_10/bigip4_5_10admin/bigipclb_outbound.html
In summary, Big-IP v4 iRule was capable of directing requests to cache arrays when it meets specific criteria like content expression and content demand status(hot or cool), and if not, redirecting to origin servers.
hope this clarifies my question...
regards,
Joseph_Hicks_36The cache rule that the original poster was looking to replicate had additional functionality surrounding hot pools and cool pools. The functionality in 4.x made it so that an array of caches wouldn't all get the same content in each cache (thereby using up all of the drive space on all of the caches with the same data).
However, it would allow content to be spread across all cache servers if the content was frequently requested within a certain period of time (making the content "Hot").
Additionally, an iRule is needed in version 9 so that in reverse proxy cache scenarios, request from the internet to a particular vip would be directed to the cache servers in a particular pool while requests from those same cache servers to the origin servers would be directed to the origin servers in that pool.
This is useful for the "vip bounceback" scenarios where users had one vip for their particular site with one pool that contained by the cache servers and the origin servers. This allows for easier cookie persistence and priority load balancing with great failover scenarios within the pool.
It would be nice to have both of these rules made and templates for download with the iRules editor.
Joe
Zafer_101134Hi,
i enable ram cache on http profile, added extensions (jpg,gif)
and i tested over f5 and direct to the web server
for example : www.abc.com/a.jpg
when resquest second times to the vip i think dont come froms f5 cache because when request direct web server get times is the same
could you help me about ram cache please
regards
zafer- These forums aren't intended for general product Technical Support. For general support questions it's best to direct your queries to the Web Support Portal so that Technical Support can assist you.
Colin
