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Why does the FF cache become excessively large, and how can I constrain it?

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  • 2 have this problem
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  • Last reply by jscher2000

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In an earlier version of FF, there was an explicit user setting for maximum cache size -- this was very helpful in constraining the bloat which regularly occurs with multiple tabs open for any extended period of time. At some point in the past few years, this setting disappeared from the up-front user option pages (but might still be around in some deeper, less-obvious setting as I have an older machine which still seems to honor its limit set long ago).

Since I routinely have to purge the webpage cache in order to regain responsiveness and function of FF when my regular tabs remain open for most of the day, I would like to see this setting return to the user-option front pages -- or know where it is located in some deeper option page.

More to the point, though, I would really like FF to constrain itself by design from bloating out on webpage cache -- reminds me too much of the 'memory leakage' problem which came to plague the Opera browser that I finally abandoned 10+ years ago for FF. I realize that many website developers these days are enamored with the bells, whistles and flashy graphics needed to gain eyeballs and earn something from clicks and click-throughs, but the present-day notion of some endless user supply of RAM grates quite hard with someone of my vintage and experience with computers since the late 1960s.

Chosen solution

Firefox will create a large cache if your hard drive or SSD has a lot of space. To constrain it:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

(2) In the search box above the list, type or paste cache.d and pause while the list is filtered

(3) Double-click the browser.cache.disk.smart_size.enabled preference to switch the value from true to false -- this is necessary to override the size, otherwise Firefox will enlarge it again in a day or two

(4) Double-click the browser.cache.disk.capacity preference to display a dialog where you can edit the size, then click OK -- if this number is 7 digits, for example, 1000000, that is 1 gigabyte; if this number is 6 digits, for example, 500000, that is 500 megabytes.

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Chosen Solution

Firefox will create a large cache if your hard drive or SSD has a lot of space. To constrain it:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

(2) In the search box above the list, type or paste cache.d and pause while the list is filtered

(3) Double-click the browser.cache.disk.smart_size.enabled preference to switch the value from true to false -- this is necessary to override the size, otherwise Firefox will enlarge it again in a day or two

(4) Double-click the browser.cache.disk.capacity preference to display a dialog where you can edit the size, then click OK -- if this number is 7 digits, for example, 1000000, that is 1 gigabyte; if this number is 6 digits, for example, 500000, that is 500 megabytes.

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Thank you very much -- I've chosen to constrain it to 80 Mb (i.e., a value of 80000), and on the older unit it was honoring the previous setting from a few years ago. IMHO, the default for new installations should be limited to <100 Mb, if not lower.

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How do I do this for an enterprise? Like in a registry or ini setting?

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Hi s.tracey, some settings are available as Registry settings. Those should be documented here:

https://github.com/mozilla/policy-templates

Otherwise, you might need to push out Autoconfig files. More info here:

Customizing Firefox Using AutoConfig