Internet Cache Sizes

[drewp]

Hi, I have a question about ISA 2004 and Internet Cache size and settings. Just noticed that mine is currently 1Gb, which i think is a bit too small seeing as we pull down about 2Gb a day.

 

One thing that worries me about making it bigger is that when the ISA Server is booted up it takes about 45 minutes before it can be logged onto as the cache is being checked. Is this normal?

 

If you have ISA 2004/6 how big is your cache size and the settings for it?

 

Thanks in advance

[tom_newton]

You don't want too big a cache - it is emptied on a "Least Recently Used" basis anyway, and as you note, it takes much longer to manage a larger cache. 1 Gig is default in our products, would go no higher than 2. Can you get cache stats on ISA?

[sahmeepee]

Can you get cache stats on ISA?

 

Yes, you can generate reports with that info in from the ISA console. I guess it might be worth increasing the cache by 50% and comparing the subsequent increase in cache hit %. We used to have a crazy 5GB dedicated to it, but I think we've dropped back to 1GB now. AFAIK our LA also cache to some extent. The doorstop^W cachepilot we have installed probably does as well!

[SYNACK]

We set ours to 50% of the amount of server ram as that is how much ISA uses by default. That works out to 1gb for us and so is also reasonable from a loading prospective.

[tom_newton]

Also worth boosting the minimum cacheable size if you can - pointless caching very small objects, as of course the cahce still has to check for updates and this can take as long as downloading the item. 10k is a good minimum.

[drewp]

Thanks for the posts so far...

 

My cache is sitting on the same mirrored disks for the OS and ISA installation. I think its a no brainier to get a reasonably priced 15k SATA HDD installed to hold the cache and see if that improves the boot up speeds.

 

I dug my ISA 2004 book out by Dr T Shinder and checked over the cache settings. They are all set at the defaults -

 

Maximum size of URL cached in memory (bytes) 12800

Return expired object only if expiration was -

At less than 50% of original TTL, but no more than 60 minutes

Percentage of free memory to use for caching - 10%

 

The caching rule is set to return the object from cache only if a valid version exists, caching dynamic content and content requiring user authentication. Not caching objects larger than 5MB and caching SSL responses. HTTP caching is also on, with the TTL at 20% of content age, TTL boundaries no less than 15 minutes, no more than 1 day.

 

Found a MS document that suggests having 10-20MB of cache for each user.