Linux tmpfs (Was: [OpenAFS] Solaris 10u6: ZFS cache?)

Brandon S. Allbery KF8NH
Thu, 13 Nov 2008 16:41:01 -0500

On Nov 13, 2008, at 09:39 , Jason Edgecombe wrote:
> Harald Barth wrote:
>>> On Linux, if you're using tmpfs as the cache, what's the difference
>>> between letting the memcache swap out vs a disk cache in tmpfs?
>> Does memcache swap out? I was convinced it did not.
> I don't believe that it does, but I was asking about the hypothetical
> case in which it would allow swapping.

It used to be said (back when warlord was maintaining linux-afs and  
Transarc 3.4a was the main release) that the memcache was much less  
efficient than the disk cache and that it was better to use disk cache  
in a ramdisk.  Both have been pretty thoroughly overhauled since then,  

brandon s. allbery [solaris,freebsd,perl,pugs,haskell]
system administrator [openafs,heimdal,too many hats]
electrical and computer engineering, carnegie mellon university    KF8NH