Tomas Ögren wrote On 11/09/06 09:59,:
1. DNLC-through-ZFS doesn't seem to listen to ncsize. The filesystem currently has ~550k inodes and large portions of it is frequently looked over with rsync (over nfs). mdb said ncsize was about 68k and vmstat -s said we had a hitrate of ~30%, so I set ncsize to 600k and rebooted.. Didn't seem to change much, still seeing hitrates at about the same and manual find(1) doesn't seem to be that cached (according to vmstat and dnlcsnoop.d). When booting, the following message came up, not sure if it matters or not: NOTICE: setting nrnode to max value of 351642 NOTICE: setting nrnode to max value of 235577 Is there a separate ZFS-DNLC knob to adjust for this? Wild guess is that it has its own implementation which is integrated with the rest of the ZFS cache which throws out metadata cache in favour of data cache.. or something..
A more complete and useful set of dnlc statistic can be obtained via "kstat -n dnlcstats". As well as soft the limit on dnlc entries (ncsize) the current number of cached entries is also useful: echo ncsize/D | mdb -k echo dnlc_nentries/D | mdb -k nfs does have a maximum nmber of rnodes which is calculated from the memory available. It doesn't look like nrnode_max can be overridden. Having said that I actually think your problem is lack of memory. For each ZFS vnode held by the DNLC it uses a *lot* more memory than say UFS. Consequently it has to purge dnlc entries and I suspect with only 1GB that the ZFS ARC doesn't allow many dnlc entries. I don't know if that number is maintained anywhere, for you to check. Mark? Neil. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
