Re: [zfs-discuss] DNLC and ARC

2008-10-30 Thread Neil Perrin
On 10/30/08 11:00, Marcelo Leal wrote: > Hello Neil, > >> Leal, >> >> ZFS uses the DNLC. It still provides the fastest >> lookup of to vnode. > > Ok, so the whole concept remains true? We can tune the DNLC and expect the > same behaviour on ZFS? Yes. > >> The DNLC is kind of LRU. An async

Re: [zfs-discuss] DNLC and ARC

2008-10-30 Thread Marcelo Leal
Hello Neil, > Leal, > > ZFS uses the DNLC. It still provides the fastest > lookup of to vnode. Ok, so the whole concept remains true? We can tune the DNLC and expect the same behaviour on ZFS? > The DNLC is kind of LRU. An async process will use a > rotor to move > through the hash chains an

Re: [zfs-discuss] DNLC and ARC

2008-10-30 Thread Neil Perrin
Leal, ZFS uses the DNLC. It still provides the fastest lookup of to vnode. The DNLC is kind of LRU. An async process will use a rotor to move through the hash chains and select the LRU entry but will select first negative cache entries and vnodes only referenced by the DNLC. Underlying this ZFS

Re: [zfs-discuss] DNLC and ARC

2008-10-30 Thread Johan Hartzenberg
DNLC seems to be independent. >From my laptop, which has only got ZFS file systems (Two ZPOOLs), the stats are: $ kstat -n dnlcstats module: unixinstance: 0 name: dnlcstats class:misc crtime 25.772681029 dir_a

[zfs-discuss] DNLC and ARC

2008-10-30 Thread Marcelo Leal
Hello, In ZFS the DNLC concept is gone, or is in ARC too? I mean, all the cache in ZFS is ARC right? I was thinking if we can tune the DNLC in ZFS like in UFS.. if we have too *many* files and directories, i guess we can have a better performance having all the metadata cached, and that is ev