Thank you for purchasing through links and ads on this site.
OWC / MacSales.com...
diglloyd Deal Finder...
Buy other stuff at Amazon.com...
Upgrade the memory of your 2019 iMac up to 128GB
Handpicked deals...

$6299.0 $4199
SAVE $2100


Sony A7R IV

NEW! Technology tour de force.

CLICK THIS AD to pre-order @ 10 AM Eastern July 18.
My review will be in-depth!


Sony gear wishlist...
√ B&H Photo PAYS THE SALES TAX FOR YOU More info...

How to Purge the File System Disk Cache

Last updated 2016-05-28 - Send Feedback
Related: how-to, memory, software

It can be confusing to evaluate available memory, because OS X can use many gigabytes for the file system cache. Thus, it can be useful to purge the OS X file system buffer cache for that reason, and another:

  • Before performing or repeating a performance test, for consistent results.
  • To assess system memory usage without a bloated disk cache.

In Terminal, use sudo purge:

diglloydMP:MPG lloyd$ sudo purge

Use of 'sudo purge' is harmless; it simply empties file system caches. The 'man' page states:

Purge can be used to approximate initial boot conditions with a cold disk buffer cache for performance analysis. It does not affect anonymous memory that has been allocated through malloc, vm_allocate, etc.

The results can be seen in Activity Monitor under memory usage. The cache will not go to zero because the system keeps some important file system structures cached.

15.6GB of cache used before sudo purge, 1.09GB after (toggle to compare).

Cached files before and after

Save the tax, we pay you back, instantly!

diglloyd.com | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2019 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__