kern/138790: [zfs] ZFS ceases caching when mem demand is high

[Andrew Snow]

Zaphod Beeblebrox wrote:

> Are we back to the old fight on dividing the system memory resource between
> cache and paging again?  This seems like a major regression for using ZFS
> over UFS.
> The idea that this might be happening has caused me to regard my ZFS store
> as a largely nfs/smb appliance.
> ZFS should be better than that.

Why?  ZFS is designed for systems with large amounts of memory to spare 
- I don't think it should be used for any system with less than 2GB.

Most brand new systems bought these days will have at least 2GB, if not 
4 or 8GB.

UFS isn't going away, it is still the filesystem preferred for embedded 
and low-end systems.



- Andrew